PSLE Barbara has a triangular piece of paper BCD with CB = CD, ∠BCD = 80° and ∠DEE = 72°. BED and CED are straight lines. She folded it along the line EF as shown.
- Find ∠g.
- Find ∠h.
(a)
Length of BC = Length of CD
Triangle BCD is an isosceles triangle.
∠CDB
= (180° - 80°) ÷ 2
= 100° ÷ 2
= 50° (Isosceles triangle)
∠g
= 180° - 72° - 50°
= 58° (Angles sum of triangle)
(b)
∠CBD = ∠CDB = 50°
∠j
= 180° - 72° - 72°
= 36° (Angles on a straight line)
∠h
= 180° - 50° - 36°
= 94° (Angles sum of triangle)
Answer(s): (a) 58°; (b) 94°