PSLEIn the figure, EFGH is a straight line, FHJK is a parallelogram and JG = JK. ∠KEF is a right angle, ∠EKF = 33° and ∠HJG = 21°.
- Find ∠l.
- Find ∠m.
(a)
∠KEF = 90° (Right angle)
∠l
= 90° + 33°
= 123° (Exterior angle of a triangle)
(b)
∠HJK = ∠HFK = 123° (Parallelogram)
∠GJK
= 123° - 21°
= 102°
∠m
= (180° - 102°) ÷ 2
= 39° (Isosceles triangle)
Answer(s): (a) 123°; (b) 39°