Multiply degrees by ฯ/180 โ 0.017453. Example: 90ยฐ ร ฯ/180 = 1.5708 radians. Radians are used in mathematics, physics and engineering.
Q: What is a gradian?
A gradian (grad) divides a circle into 400 parts (vs 360 degrees). 1 grad = 0.9ยฐ. Used in surveying and civil engineering. A right angle = 100 gradians = 90 degrees.