Inscribed angle in a circle
The question
degrees
Center angle 40°, find the angle on the circle
How it works.
same arc, two angles
center = 2 × circlesocircle = center ÷ 2
40 ÷ 2=20
- 01
Both marked angles stand on the same arc — the two chords and the two radii end at the same two points on the circle.
- 02
The angle at the center is always twice the one on the circle, wherever on the far arc that point sits. Here the center angle is the one given, so this is a halving.
- 03
Half of 40 is 20, so the angle on the circle is 20°.