The figure is not drawn to scale. HJLM is a square and GHM is an equilateral triangle. JKL is an isosceles triangle. GLK is a straight line.
- Find ∠MGL.
- Find ∠JKL.
(a)
∠LMH = 90°
∠GMH = 60° (Equilateral triangle GMB)
∠GML
= 90° + 60°
= 150°
∠MGL
= (180° - 150°) ÷ 2
= 30° ÷ 2
= 15° (Isosceles triangle)
(b)
∠GLJ
= 90° - ∠GLM;
= 90° - 15°
= 75°
∠KLJ
= 180° - ∠GLJ
= 180° - 75°
= 105° (Angles on a straight line)
∠JKL
= (180° - ∠KLC) ÷ 2
= (180° - 105°) ÷ 2
= 75° ÷ 2
= 37.5° (Isosceles triangle)
Answer(s): (a) 15°; (b) 37.5°
