GB-42-02-001 · Cyclic quadrilateral

Diagram not accurately drawn

A, B, C and D lie on a circle in that order. Angle DAB is 68°. Find angle BCD and give a reason.

Circle Theorems: Cyclic Quadrilateral Booklet p. 85 & p. 86

Method

Write each calculation beside the geometric reason that justifies it

Worked Example (GB-42-02-001)

Maths	Reason
$\angle BCD=180^\circ-68^\circ=112^\circ$	Opposite angles of a cyclic quadrilateral sum to 180°.

Ans = 112°