Finding Missing Side Lengths

Grade 3β€’45 minutes

Learning Objective

I can use addition and subtraction to find the unknown side length of a polygon.

Practice Questions

This lesson includes 7 practice questions to reinforce learning.

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1. Explain in your own words how to find a missing side length of a shape when you know the lengths of some of the other sides.

2. Look at this shape: It has sides of 3 cm, 5 cm, 2 cm, and a missing side. If the top side is 5 cm and part of the bottom side is 2 cm, what operation (addition or subtraction) would you use to find the missing side?

3. A rectangle has a top side of 8 inches and a bottom side. One part of the bottom side is 5 inches. What is the length of the missing part of the bottom side?

...and 4 more questions

Educational Video

Finding Perimeter when a Side Length is Missing (Composite Figures) | Math with Mr. J

Math with Mr. J

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