PSLEIn the figure, EFGH is a straight line, FHJK is a parallelogram and JG = JK. ∠KEF is a right angle, ∠EKF = 38° and ∠HJG = 20°.
- Find ∠l.
- Find ∠m.
(a)
∠KEF = 90° (Right angle)
∠l
= 90° + 38°
= 128° (Exterior angle of a triangle)
(b)
∠HJK = ∠HFK = 128° (Parallelogram)
∠GJK
= 128° - 20°
= 108°
∠m
= (180° - 108°) ÷ 2
= 36° (Isosceles triangle)
Answer(s): (a) 128°; (b) 36°