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# Right angles in shapes (informal definition)

CCSS.Math:

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.

## Challenge problem

## Want to join the conversation?

- is a diamond considered a quadrilateral(97 votes)
- Yes cause it still has 4 sides(40 votes)

- why do they have to have a right angle(12 votes)
- 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.(20 votes)

- what is a quadrilatelar(11 votes)
- It is a shape with four side like a square or rectangle.🙂(13 votes)

- why is a dimaond considerd a quadiraterial(7 votes)
- 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.(6 votes)

- (>o<) that was easy. man when will it end though.(6 votes)
- Difference between quadrilaterals a parallelogram?(5 votes)
- Yes, that is correct! 😁(3 votes)

- how does that guy right so good on a computer(5 votes)
- 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!(5 votes)

- I do not get that a petagon have 2 right angls.(4 votes)
- Draw three sides of a square (the bottom line and the two side lines) Then put a peaked roof on it like the roof of a house.

There you have five lines which is the definition of a pentagon (when you see the prefix PENT, that means 5) In this case, you will also see the two right angles where the bottom line and the two vertical lines meet.

Get the idea?(7 votes)

- At8:54

do all concave shapes have to have an angle over 180 degress?(4 votes)- yes, they need at least 180 degrees.a triangle has 180(6 votes)

- The angles have to be ALWAYS squares right?(4 votes)
- no it doesn't always have to be a square(6 votes)