The figure is not drawn to scale. Triangle EFD is an isosceles triangle. Triangle BCD is an equilateral triangle. ∠FDE is
25 of ∠CBD and ∠CDF = ∠BDE.
- Find ∠CDF.
- Find ∠BED.
(a)
∠CDB = 60° (Equilateral triangle)
∠FDE
= ∠CDB x
25 = 60° x
25 = 24°
∠CDF = ∠BDE
∠CDF
= ∠CDB - ∠FDA) ÷ 2
= (60° - 24°) ÷ 2
= 36° ÷ 2
= 18° (Isosceles triangle)
(b)
∠BED
= 180° - ∠CBD - ∠CDF
= 180° - 60° - 18°
= 102° (Angles sum of triangle)
Answer(s): (a) 18°; (b) 102°