High School Geometry Activities

To get ready for teaching high school geometry again, I'll be adding a bunch of geometry coloring worksheets, geometry error analysis activities, geometry escape rooms and geometry task cards here that my students will complete next year as part of our curriculum.

Over the last few weeks, I've been making some new geometry activities to get ready for my new teaching assignment in the fall. It has been a while since I've taught high school geometry, and the students I will be teaching in the fall will need a lot of support. So I've been building up a collection of engaging geometry activities for students that will support their learning while also being fun. They'll all be here (sorted by most recent).


angles, lines, rays and line segments coloring worksheet activity

After starting the year reviewing integers, order of operations, scientific calculator basics and some translating written expressions into symbols, we'll get into geometry fundamentals. We'll start fundamentals by identifying angles, lines, rays and line segments. 


angles lines rays line segments matching activity

After notes, students will complete a matching activity for identifying angles, lines, rays and line segments, then this angles, lines, rays and segments coloring worksheet


naming angles coloring worksheet activity

When I posted that coloring activity on Facebook, a teacher mentioned his students having trouble naming angles. So I made this naming angles coloring worksheet



After naming angles, we'll move into writing congruency statements. We'll focus on writing congruent angles and line segments statements during this unit and complete this congruency statements 2 truths and a lie


Then we'll get into solving for the lengths of line segments, and I know that students will need a lot of support solving equations. My students next year will be freshmen in small group special education. We call the class applied geometry, and they will be taking it before taking high school algebra. I have used this solving equations flowchart most of my years teaching to support students solving equations.


line segment addition 2 truths and a lie error analysis activity

I love 2 truths and a lie activities because of how they focus students on identifying mistakes. After we practice solving line segment equations in our notes, students will complete this line segment addition 2 truths and a lie. On each card there are 3 statements. Students figure out the error (the lie) then fix it on their answer sheet.


Students will complete this classifying angles coloring worksheet activity if they need a refresher on identifying acute, obtuse, right and straight angles.

If students seem to need a refresher on identifying angles by measurement, I'll give them this classifying angles coloring worksheet activity.



Task cards are nice for chunking material to make assignments less overwhelming for students. When I taught geometry in the past, students completed this midpoints, angle bisectors and angle sums activity. There are just 4 cards with multiple questions, so students can focus on one skill at a time.



identifying angle pair relationships (complementary, supplementary, vertical angles) error analysis activity

Next, we'll get into supplementary, complementary and vertical angles notes, then practice identifying angle pair relationships and solving for angle measurements.



Students really like these escape rooms, so to practice solving for the measures of these angle pairs, I'll give them the printable version of this angle pairs relationship escape room. The puzzles get harder as the activity progresses, so every student should be able to complete at least a few of the puzzles for practice.


solving complementary, supplementary and vertical angle equations

For more complex angle pair equations, I also have this complementary, supplementary and vertical angles 2 truths and a lieMy students are going to keep separate warm-up notebooks this year, so I might give individual cards as warm-ups for their notebooks. I like spending extra time on warm-ups (20 minutes) because it breaks up the time and reviews important material from the previous class.



This will finish up our fundamentals unit, after which we'll move into coordinate geometry. Hopefully there will be some board room for my large magnetic coordinate plane because I already know students will struggle with plotting coordinates. I'm going to present coordinates as (time, height) or (time, amount) so that the x and y values feel different from each other.


Pythagorean Theorem in the coordinate plane

Students will be introduced to the Pythagorean Theorem in the coordinate plane by first identifying each right triangle's vertex coordinates, then counting to find leg lengths, then using the Pythagorean Theorem to calculate hypotenuse lengths.



We'll then move on to this Pythagorean Theorem escape room, a 2 truths and a lie error analysis, or both depending on how they're doing.



Next up is calculating missing midpoints and endpoints, and I remember students struggling with this from the last time I taught geometry. We'll start with finding the midpoints and missing endpoints of horizontal and vertical segments, then move to diagonal segments. As an intro activity, I'm going to give students this hands-on endpoints and midpoints worksheet. Students will use their right triangle to measure the line segments then fill in each table. There's a 4-question exit ticket at the end.


High School Geometry Bundle


I still have a lot to make to be ready for teaching this class next year. All of my geometry activities are in this high school geometry activities bundle, and all new geometry activities will be added in there, too.



Increasing and Decreasing Finder Tool for Graphs

How to find the increasing and decreasing intervals of graphs with this increasing and decreasing finder tool

Do your algebra students struggle with finding the increasing and decreasing intervals of graphs? This increasing and decreasing finder tool guides students where to look when finding the increasing and decreasing intervals.



Students watch the graph move up and down the ruler on the side.


domain and range finder tools w/ increasing and decreasing


"These helped my algebra students so much! The directions on each finder were so helpful...especially when the graph has arrows and not endpoints." - Elizabeth Y


The increasing and decreasing tool was added to a similar domain and range finder tool that guides students where to look when finding domain and range. See the domain & range / increasing & decreasing tools here.




How to Stop Students from Second-Guessing on Math Exams


Are your students constantly erasing correct answers and second-guessing themselves? Veteran teachers offer their best advice to new teachers.

The brain is a funny thing. We've evolved these giant frontal lobes that can plan years in advance, but throw in a bit of test anxiety and we're suddenly running from a lion at dusk. When the brain detects danger, that massive frontal cortex shuts off and is just there taking up space.


If I had to estimate, every single student I have ever had in any of my special education math classes has had some level math anxiety. I have my theories as to why this is, but in this post I want to instead focus on ways to help students overcome this anxiety when taking tests so that they don't doubt their answers.  


How to stop students second-guessing their math


I asked teachers on Facebook what they do to help students with this, and got a bunch of great advice. Their advice is below. If you'd like to read the original thread, it's here.


Compound Interest Cheat Sheet

In this post, is the free compound interest reference sheet we use during our exponential functions unit in algebra 2.

This week, the plan is to finish learning about compound interest so that we can squeeze in projectile motion next week before starting final exam review the week after. It'll be tight, but that's the goal! Hard to believe there are only a few weeks left.


We started our exponential functions unit learning how to graph exponential functions by building tables, identifying a and b given a table, and writing the equations of exponential graphs with the y-intercept and f(1) highlighted.



We then moved on to compound interest compounding annually, then compounding more often. Today students started a compound interest escape room that covers compounding annually, quarterly, monthly, and daily. The escape room also comes as self-checking digital, but we used the printable version. It's more forgiving and keeps students offline.


Free Exponential Functions Growth - Decay - Compound Interest Cheat Sheet


Today, I made students this exponential functions cheat sheet that they can use as we finish up the escape room, exponential decay, and on their upcoming quiz as an IEP accommodation.


For decay, I may also give students this friendly percents reference depending on how things go. We may just stick with (1 - r), but I'd like them to have another perspective for finding the base of decay functions.



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2 Percent of a Number Cheat Sheets


In this post, there are two free percent of a number cheat sheets for a consumer math unit on calculating percentages of numbers and calculating discounts. Each can be added to student notebooks as a reference when learning how to calculate percentages.


Percent of a number cheat sheet
Percent of a number cheat sheet

The first percent sheet reminds students of the divisor when calculating the percent of a number. For example, We can divide 125 by 5 to find that 25 is 20% of 125. This sheet prints on half a page to fit into a student notebook.


Friendly percentages cheat sheet
Friendly percentages cheat sheet


The second is a friendly percentages reference that's helpful for calculating discounts. If a shirt is 15% off, we can calculate the shirt's price by finding 85% of the original cost of the shirt. I always find this easier than calculating 15% then subtracting that amount from the original price.

This friendly percentages sheet can also be referenced during an exponentials unit when calculating decay. If the value of a car is depreciating by 15% per year, we can use .85 as the exponential's base.



The two sheets are found free in the same download here: Free percent of a number cheat sheets



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How to Write an Exponential Function Equation Reference Sheet

how to write exponential function from table free step-by-step guide sheet

It's almost the Massachusetts version of spring break here (April vacation), term 4 just started (hard to believe!) and we just began on our exponentials unit in algebra 2. This is going to be a super short post just to share a cheat sheet to help students remember how to write an exponential function equation given two points.



The sheet walks students through how to write exponential function equations from a table of values, including the y-intercept and one other point. Students are shown how to solve for the exponential's base b, then how to write the equation using this base and information from the table.


You can download this cheat sheet free here.



Normal Distribution Curve Reference Sheet in Algebra 2 Statistics

 Normal distribution curve reference sheet for algebra 2 statistics

We started our statistics unit in algebra 2 and so far have reviewed box and whiskers plots, dot plots, histograms and learned about skewed data, interquartile range and experimental vs. observational studies. Last week, we started learning about normal distribution and will be on this topic for a little while. We move onto z scores tomorrow.


We gave students a simplified version of the curve with whole number percentages to make calculations easier to manage. I wanted to share this reference with you in case it would be helpful for your students, too. If you'd rather keep the decimals in the percentages, there's also a blank curve in the file.


We printed a bunch on this orange paper (the orange reminded me of that funny normal distribution ghost meme) and laminated them so that students can write on their curves while working.




You can download this normal curve reference here from my Google Drive.


Probability error analysis activity
Probability error analysis

If you teach probability, I recently made a "2 truths and a lie" error analysis activity that covers independent and dependent compound probability.


This data and statistics activity can either be used as a review of mean, median, mode, outlier, skew, dot plot, histogram, box and whiskers, or as an introduction to a statistics unit in algebra as a way to refresh student memories of these topics.
Data and Statistics Activity

Before we got into symmetrical data analysis, we reviewed skewed data and completed this data and statistics activity. It covers mean, median, mode, skew, histograms, dot plots and box and whiskers plots.


Browse statistics activities


More algebra 2 activities