PSLE Lucy has a triangular piece of paper BCD with CB = CD, ∠BCD = 84° and ∠DEE = 69°. 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° - 84°) ÷ 2
= 96° ÷ 2
= 48° (Isosceles triangle)
∠g
= 180° - 69° - 48°
= 63° (Angles sum of triangle)
(b)
∠CBD = ∠CDB = 48°
∠j
= 180° - 69° - 69°
= 42° (Angles on a straight line)
∠h
= 180° - 48° - 42°
= 90° (Angles sum of triangle)
Answer(s): (a) 63°; (b) 90°