PSLE QRST and RTUV are rhombuses. SWT is a straight line.
- Find ∠TRW.
- Find ∠STU.
(a)
∠RTS
= (180° - 108°) ÷2
= 72° ÷ 2
= 36° (Isosceles triangle)
∠TRW
= 180° - 128° - 36°
= 16° (Angles sum of triangle)
(b)
∠RVU
= 360° - 275°
= 85° (Angles at a point)
∠RTU = ∠RVU = 85° (Rhombus)
∠STU
= 85° - 36°
= 49°
Answer(s): (a) 16°; (b) 49°