How to convert from degree to radian or radian to degree?
Using calculator:
→ What is 225 degree in radian?
We know that π = 180 degree so what we could do is using cross multiply:
How to convert from degree to radian or radian to degree?
Without using a calculator:
30 degree = π/6 radian
Proof: π = 180 degree
180/6 = 30
60 degree = π/3 radian
Proof: π = 180 degree
180/3 = 60
90 degree = π/2 radian
Proof: π = 180 degree
180/2 = 90
45 degree = π/4 radian
Proof: π = 180 degree
180/4 = 45
These are the different degrees of special right triangle and we can use them to determine the measure of triangles, in radian, without the use of calculator.
30-60-90 triangle
45-45-90 triangle