Central angle — Geometry, what it means and where it is taught
An angle whose vertex is the centre. Equal to its arc.
Taught in Geometry.
Where it is taught
What it rests on
Work through these first if this one does not settle.
- Vertex — A flat surface; a line where two faces meet; a corner point.
- Arc — Part of the edge; a "pizza slice" bounded by two radii.
Practise this idea
4 questions in the course bank use Central angle, in Circle Angles, Arcs & Chords, Radians & the Unit Circle.
Problem 1
A central angle cuts an arc of 70°. Find the angle.
Worked answer
70
70°
Problem 2
A central angle is 124°. Find the inscribed angle on the same arc.
Worked answer
62
124 ÷ 2 = 62°
Problem 3
A circle of radius 6 has a central angle of π3. Find the arc length. Give the coefficient of π.
Worked answer
2
6 · π3=2π
Problem 4
A circle of radius 10 has a central angle of 1.5 radians. Find the arc length.
Worked answer
15
10 × 1.5 = 15