The triangle POR is - JAMB Mathematics 2002 Question

< PRQ = 180^o - 128^o = 52^o = < R

< P + < R + < Q = 180^o

76^o + 52^o + < Q = 180^o

128^o + < Q = 180^o

< Q = 180^o - 128^o

= 52^o

(\bigtriangleup)PQR is an isosceles