Measuring angles

Measuring angles

First Let’s Review! • What type of angle is this? Obtuse

First Let’s Review! • What type of angle is this? Acute

First Let’s Review! • What type of angle is this? Right

What is this called? Ray Ray Vertex

What are these called? 1 Sides 2

What is this called? Angle

Now Let’s talk about degrees • A degree tells us the exact measurement of an angle. A right angle measures 90

Now Let’s talk about degrees • An obtuse angle is more than 90 so it will always be larger. More than 90 90 Right angle Obtuse angle

Now Let’s talk about degrees • An acute angle is less than 90 so it will always be smaller. 90 Less than 90 Right angle Acute angle

Now Let’s talk about degrees • A straight angle measures 180 .

Lets see if you can identify some angles. • Put your hand on your head if its more than 90. • Touch your ears if it’s 90. • Touch your nose if it’s less than 90.

So how do we measure angles? • With this. A protractor

Lets measure this angle. Make sure this edge is lined up on the protractor too. First you must line the center of the protractor with the vertex.

Lets measure this angle. Once the protractor is in place we check the measurement here.

Lets measure this angle. The measurement reads 90

Watch me as I demonstrate one on the board. • Now you try the problems on page 40.

Measuring angles