Angle at the circumference

Answer explanation

The angle at the centre is twice the angle at the circumference of a circle.

Point D is the centre of the circle.

A, B and C lie on the circumference of the circle where AB is the diameter.

Calculate the size of angle ABC.

Answer explanation

ABCD is a cyclic quadrilateral.

E is the centre of a circle.

Calculate the size of the reflex angle at E.

A, B and C are points on the circle with radius CD.

Calculate the size of angle BAC.

Answer explanation

180 −( 74 + 59 ) = 47

 

47÷2 = 23.5 (angle at the centre is twice the angle at the circumference)

Answer explanation