Find the Interior Angles of Shapes

Once your students have an understanding of acute, right and obtuse angles, the next step is being able to identify these angles in common two-dimensional shapes such as triangles, squares, pentagons, hexagons and octagons.

In regular shapes, all interior angles are the same size. This sorting activity has been designed to help your students consolidate their understanding of the interior angles of regular polygons. Students are required to sort shapes (with certain angles identified) and shape statements under the correct angle range headings, as outlined below:

• Less than 100 degrees
• 100 to 125 degrees
• 126 to 150 degrees
• 151 to 200 degrees
• 201 to 300 degrees
• Over 300 degrees

How to Complete This Interior Angles Sorting Activity

This hands-on sorting activity has been designed to help your students classify a variety of polygons based on their interior angles. Complete the activity by following the instructions below. 

1. Print and cut the six heading cards and the 24 sort cards.
2. Sort the shapes and shape statements on the sort cards under the correct headings. 
3. Check answers using the answer key provided.

The resource includes:

• 1 x instruction page
• 6 x sort headings 
• 24 x triangle sort cards
• 1 x answer key.

This resource is perfect as a math group activity, a whole-class review or an independent fast-finisher activity. 

Tips for Scaffolding and Extension

At Teach Starter, we know you’re always looking for ways to adapt tasks to cater to the individual learning needs of students. Here are some tips on how you might extend this activity for your more-confident learners, as well as how to support those students who need a little extra help to stay on track.

• Challenge Your High-Fliers – This activity requires students to place the sorting cards underneath angle-size headings which depict an angle range e.g. 100 to 125 degrees. Extend your more-capable mathematicians by having them calculate the exact angle size for each sort card and record these in their workbooks.
• Support Your Less-Confident Learners – Some students may benefit from scaffolding materials to assist them while sorting the shapes. Provide examples of each polygon with the interior angles labeled. Students may also benefit from using a protractor to help them determine the size of each angle.

Easily Prepare This Resource for Your Students

Use the dropdown icon on the Download button to select between the editable Google Slides or easy-print PDF version of this resource.

Print on cardstock for added durability and longevity. Place all pieces in a folder or large envelope for easy access.

Be sure to remove the answer key before distributing this activity to your students!

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This resource was created by Kaylyn Chupp, a teacher in Florida and a Teach Starter collaborator.

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