GB-42-06-001 · Equal tangents

Diagram not accurately drawn

PA and PB are tangents from an external point P to the same circle. PA = (6x + 15) cm and PB = 75 cm. Find x. Give a geometric reason for your equation.

Circle Theorems: Two Tangents from an External Point Booklet p. 85 & p. 86

Method

Write each calculation beside the geometric reason that justifies it

Worked Example (GB-42-06-001)

Maths	Reason
$6x+15=75$	Tangents from the same external point are equal in length.
$6x=60\Rightarrow x=10$	Subtract the same number from both sides, then divide by the coefficient.

Ans = 10