Question

What is -pi in degrees?

Answer 1

`-pi` radians `= -180^o`

A radian is the angle subtended by an arc of a circle of length equal to the radius. If a circle has radius 1, then an angle of 1 radian defines an arc whose curved length is 1. `2pi` radians will take you once round the circle.

Degrees divide the angle of a complete circle into 360 divisions. `360^o` takes you once round the circle.

So `2pi` radians is the same as `360^o` and `pi` radians is `180^o`.