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## Geometry (all content)

### Course: Geometry (all content)>Unit 5

Lesson 1: Quadrilateral types

# Right angles in shapes (informal definition)

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 two right angles.

## Practice

First, let's study some more examples.
Now, try it yourself.
How many right angles are in this square?

How many right angles are in this pentagon?

## Challenge problem

How many right angles does this shape have?

## Want to join the conversation?

• is a diamond considered a quadrilateral
• Yes cause it still has 4 sides
• why do they have to have a right angle
• It's just one of the 3 main angles in math.
Acute angles are angles that are less than 90 degrees.
Right angles are angles that are exactly 90 degrees.
Obtuse angles are angles that are more than 90 degrees.
You'll work with these three types of angles a lot more as you advance in math.
• what is a quadrilatelar
• It is a shape with four side like a square or rectangle.🙂
• why is a dimaond considerd a quadiraterial
• I like to think of a diamond as an adjusted square so it is a quadrilateral. It is also a quadrilateral because it has 4 sides.
• how does that guy right so good on a computer
• My theory is that he is either trained to do it so well, or he uses a virtual pad and pen to draw.

Have a nice day!
• it said challenge question and I was like 😒
• (>o<) that was easy. man when will it end though.
• not for everyone
• I do not get that a petagon have 2 right angls.