Geometry Lab for teachers
Free, interactive geometry and trigonometry tools, with a printable student activity and an answer key for twelve topics. Students need no accounts, and everything runs on school Chromebooks with nothing to install.
Ready-made classroom activities
Each activity is a one-page worksheet that walks students through a real tool’s controls, with observation, prediction and calculation questions. Times are for a typical class working in pairs.
Standards connections refer to the Common Core State Standards for Mathematics. We list one only where the activity clearly supports it.
More printables
Three ways to use the tools in class
Assign it in Google Classroom
Use a Share to Google Classroom button (on every tool, guide and worksheet) to post a tool as an assignment or material, and attach the worksheet. Students open it straight from Classroom.
Project it for a demo
Run a tool on the board and ask the class to predict before you change a value: what happens to the area when the scale factor doubles, or to the third side when the angle opens up?
Station rotation
Set up three or four tools on shared devices, each with its worksheet. Groups rotate every 15–20 minutes and compare their findings at the end.
Built for school devices
No installs, plug-ins or logins. The tools run in the browser on Chromebooks, laptops and tablets, and every calculator also works with a keyboard.
Student privacy
Students never create accounts, and we never ask for names, email addresses or answers. Worksheets are completed on paper or in your own Classroom assignment, so student work never reaches this site.
Students who open a tool from Google Classroom, Canvas or Schoology see no ads. The same applies to links shared with the buttons on this site. To remember this, the student’s browser stores only an “ad-free until” date, for 30 days.
To be transparent: the site uses Google Analytics to measure how pages are used (such as pages viewed, device type and approximate country), and it shows a few labeled Adsterra banner ads to other visitors to keep the tools free. Read the privacy policy for details.
About the answer keys
Every number in an answer key is calculated with the same math the tools use, so students’ readings will match. Answer keys are not linked from student pages and are hidden from search engines, but they are not password-protected.
Tell us what you need
Using Geometry Lab with your class? We would love to hear what worked, what didn’t and which topic you would like next: info@geometrylab.net.
Teacher questions
Wondering about the why? Start here.
Is Geometry Lab free for classrooms?
Yes. Every tool, student activity and answer key is free, with no sign-up and no limit on the number of students.
Do students need accounts or logins?
No. Students open a link and start exploring. Nothing is saved to an account, and worksheets are completed on paper or in your own Classroom assignment.
Does it work on Chromebooks and tablets?
Yes. The tools run in any modern browser, including Chrome on school Chromebooks and Safari on iPads, with nothing to install. JavaScript must be enabled.
Will my students see ads?
Students who open a tool from Google Classroom, Canvas or Schoology, or through a Share to Google Classroom link on this site, see no ads on that device for 30 days. Other visitors see a few clearly labeled banner ads, which keep the site free.
Which standards do the activities support?
Where an activity clearly fits, it lists the Common Core math standard it connects to, such as 8.G.B.7 for the Pythagorean theorem or HSG-SRT.D.11 for the laws of sines and cosines. The tools are supplements rather than complete lessons, so use them alongside your curriculum.
Can I adapt the worksheets?
Yes. Print them as they are, paste the questions into your own Classroom assignment, or build a custom practice sheet with the worksheet generator.