Radian

A radian is a unit for measuring angles based on the radius of a circle: one radian is the angle at the centre that cuts off an arc equal in length to the radius. A full turn is $2\pi$ radians, so $180^\circ=\pi$ radians, which converts between the two units.

You meet Radian in the Circular Measure chapter of SPM Additional Mathematics. Knowing the term precisely matters in the exam: questions often hinge on reading a keyword correctly, and because SPM marking is analytic, using the right definition in your working helps secure method marks.

Our teachers make sure a student can not only recite what Radian means but use it fluently in a full solution.

Because the SPM Add Math paper is bilingual (BM/EN), it helps to know this term in each language: Radian (EN) · Radian (BM) · 弧度 (中文)

Other key terms from the Circular Measure chapter you may want to check:

• Arc Length
• Sector
• Area of a Sector
• Segment of a Circle
• Angle Subtended at the Centre