In the figure, ADGK is a rectangle, GHKL is a rhombus and DEFG is a parallelogram. ∠GHK = 78° and ∠FGH = 93°.
- Find ∠CGD
- Find ∠GFE
(a)
∠KLG = ∠KHG = 78°
∠LGK
= (180° - 78°) ÷ 2
= 102° ÷ 2
= 51° (Isosceles triangle)
∠CGD
= 90° - 51°
= 39°
(b)
∠DGF
= 360° - 93° - 90° - 51°
= 126° (Angles at a point)
∠EFG
= 180° - 126°
= 54° (Interior Angles, DG//EF)
Answer(s): (a) 39°; (b) 54°