PSLE Ivory has a triangular piece of paper HJK with JH = JK, ∠HJK = 78° and ∠KLL = 68°. 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° - 78°) ÷ 2
= 102° ÷ 2
= 51° (Isosceles triangle)
∠n
= 180° - 68° - 51°
= 61° (Angles sum of triangle)
(b)
∠JHK = ∠JKH = 51°
∠q
= 180° - 68° - 68°
= 44° (Angles on a straight line)
∠p
= 180° - 51° - 44°
= 85° (Angles sum of triangle)
Answer(s): (a) 61°; (b) 85°