Question

How do you convert 25degrees into radian measure?

Answer 1

I know that `180°` is `pi` radians (consider the length of a half circle arc; it spans an angle of `180°` and its length is `pir` or half the entire circle perimeter. But radians is (arc length)/(radius), so for your half circle you have that also spans `pir/r=pi` radians).
Now you can say that:
`(180°)/(25°)` must have the same result as `pi/x` where `x` is the corresponding measure of `25°` in radians:
Finally:
`x=(25°)/(180°)pi=5/36pi`