CONGRUENCE OF TRIANGLES 1

Prove that the following triangle is isosceles.

solution

Given: triangle QRT with R produced to X.

Required to prove: ∆QRT is isosceles

Proof: 

QX = XT (given)

<RXQ = <RXT = 90⁰ (<QXT is a straight angle)

RX = XR (common line)

∆RXQ ≡ ∆RXT by SAS rule

Hence ∆QRT is isosceles (proved)