Radian

How it is used

Standard in calculus and higher maths, where formulas such as the derivative of sin x assume the angle is in radians. You convert between degrees and radians using π radians = 180°. Remember to switch your calculator to radian mode (RAD) when needed.

Example sentences

1. Convert 60 degrees to radians: the answer is π/3.

2. My answer was wrong because the calculator was set to degrees instead of radians.

Common collocations

• in radians
• convert to radians
• radian measure
• radian mode

Related terms

• angleThe amount of turn between two lines or rays that meet at a point, measured in degrees or radians.
• sineIn a right triangle, the ratio of the side opposite an angle to the hypotenuse; it is written sin, so sin 30° = 0.5.
• cosineIn a right triangle, the ratio of the side next to an angle (the adjacent side) to the hypotenuse; it is written cos, so cos 60° = 0.5.
• radiusThe distance from the centre of a circle or sphere to any point on its edge; it is half the diameter.

More terms: Trigonometry

• hypotenuse
• tangent