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Course: US Math sandbox > Unit 6

Lesson 3: Lindsay's sandbox
Math
US Math sandbox
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Lindsay's sandbox
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Linsicle-10

Google Classroom
Identify right angles in shapes. 

Introduction

Many shapes have corners. We call a corner a right angle if we can fit a little square perfectly inside it.

Consider the trapezoid

Let's draw a square in each corner.
In which corners did the little square fit perfectly?
The trapezoid has 2 right angles.

Practice

First, let's study some more examples.

Now, try it yourself.

How many right angles are in this square?
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi

How many right angles are in this pentagon?
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi

Challenge problem

How many right angles does this shape have?
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi

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