How_To_Be_Good_At_Math

GEOMETRY • DEGREES 231

Degrees

We use units called degrees to precisely describe an amount of

turn, which is how we measure the size of an angle. The symbol

for degrees is a small circle, like this: °.

This shows

an angle of

100 degrees (100°).

Here is a full

turn divided

into degrees. A

full turn always has

360 degrees.

This is one

degree (1°).

It's equal to^1 ⁄ 360

of a full turn.

This shows ten

degrees (10°). We

can see that the angle

made by this turn is

ten times larger than

the 1° angle.

Centre

DAY

360

There are

360 degrees

in a full turn.

REAL WORLD MATHS

Why 360 degrees?

One theory to explain why there are 360°

in a full turn is that ancient Babylonian

astronomers divided a full turn into 360

parts, because their year was 360 days long.

230_231_What_is_an_Angle.indd 231 29/02/2016 18:05