PSLE Zoe has a triangular piece of paper CDE with DC = DE, ∠CDE = 84° and ∠EFF = 71°. CFE and DFE are straight lines. She folded it along the line FG as shown.
- Find ∠h.
- Find ∠j.
(a)
Length of CD = Length of DE
Triangle CDE is an isosceles triangle.
∠DEC
= (180° - 84°) ÷ 2
= 96° ÷ 2
= 48° (Isosceles triangle)
∠h
= 180° - 71° - 48°
= 61° (Angles sum of triangle)
(b)
∠DCE = ∠DEC = 48°
∠k
= 180° - 71° - 71°
= 38° (Angles on a straight line)
∠j
= 180° - 48° - 38°
= 94° (Angles sum of triangle)
Answer(s): (a) 61°; (b) 94°