Question on: JAMB Mathematics - 2000

Δ PQR is isosceles

∴∠PRQ = 30^o

Also in Δ PQR
^{^}Q = 180 -(30 + 30)

= 120^o

PQRS is a cyclic quad

∴^{^}S + ^{^}Q = 180(opp ∠s of a cyclic quad)

S + 120 = 180

S = 60^o

In ΔPSR

x + 50 + 60

= 180(sum of ∠s of a Δ)

x + 110 = 180

x = 180 - 110

x = 70^o