The figure is not drawn to scale. ST//VU and UT//WS. Triangles SWT and TUV are isosceles triangles. Find
- ∠i
- ∠j.
(a)
∠TUV = ∠TSW = 72° (UT//WS, TS//UV)
∠STW
= (180° - 72°) ÷ 2
= 108° ÷ 2
= 54° (Isosceles triangle)
∠UTV
= 180° - 72° - 72°
= 36° (Isosceles triangle)
∠i
= 180° - 72° - 54° - 36°
= 18° (Interior angles, TS//UV)
(b)
∠j
= 180° - 25° - 18°
= 137° (Angles sum of triangle)
Answer(s): (a) 18°; (b) 137°