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Radian

See how to write and use the angle in radian measure.
5 examples and their solutions.

Radian

Formula

(rad) = (°)⋅π180
Radian is a way to write the measure of an angle.
180° = π
Unit: rad (can be omitted)

Example

30° → rad?
Solution

Example

π4 → °?
Solution

Mostly Used Angles in Radian

Formula

°rad
0
30°π6
45°π4
60°π3
90°π2
180°π
270°2
360°

Length of an Arc (Radian)

Formula

Example

Length of AB = ?

Solution

Area of the Sector of a Circle (Radian)

Formula 1

Example

Area?

Solution

Formula 2


A = 12rl
l: Length of an Arc

Example

Area?

Solution