The figure, not drawn to scale, is made up of an isosceles triangle and a rhombus. ∠c = ∠d, ∠a is twice ∠d, ∠b is thrice ∠e and ∠c is less than ∠e by 36°.
- Find ∠c.
- Find the difference between ∠a and ∠c.
(a)
∠c = 1 u
∠d = 1 u
∠e = 1 u + 36°
1 u + 36° + 1 u + 36° + 1 u = 180° (Angles sum of triangle)
3 u + 72° = 180°
3 u = 180° - 72° = 108°
1 u = 108° ÷ 3 = 36°
∠c = 1 u = 36°
(b)
∠a = 2 u
∠a - ∠c
= 2 u - 1 u
= 1 u
= 1 x 36°
= 36°
Answer(s): (a) 36°; (b) 36°