The figure is not drawn to scale. CDFG is a parallelogram. ∠GCO is 58° and ∠FDE is 25°. CDE is an isosceles triangle and CD = DE.
- Find ∠OED.
- Find ∠CGF.
(a)
∠DOC = 58° (Alternate angles, CG//DF)
∠DOE
= 180° - 58°
= 122° (Angles on a straight line)
∠OED
= 180° - 122° - 25°
= 33° (Angles sum of triangle)
(b)
∠DCO = 33° (Isosceles triangle CDE)
∠CGF
= 180° - 58° - 33°
= 89° (Interior angles, CD//GF)
Answer(s): (a) 33°; (b) 89°