PSLE Lynn has a triangular piece of paper HJK with JH = JK, ∠HJK = 80° and ∠KLL = 72°. HLK and JLK are straight lines. She folded it along the line LM as shown.
- Find ∠n.
- Find ∠p.
(a)
Length of HJ = Length of JK
Triangle HJK is an isosceles triangle.
∠JKH
= (180° - 80°) ÷ 2
= 100° ÷ 2
= 50° (Isosceles triangle)
∠n
= 180° - 72° - 50°
= 58° (Angles sum of triangle)
(b)
∠JHK = ∠JKH = 50°
∠q
= 180° - 72° - 72°
= 36° (Angles on a straight line)
∠p
= 180° - 50° - 36°
= 94° (Angles sum of triangle)
Answer(s): (a) 58°; (b) 94°