In the figure, QR is a straight line. ∠PSQ = 90°, ∠TSU is equal to ∠USR but 21° more than ∠PST.
- What line is perpendicular to QR?
- Find ∠TSU.
(a)
Line PS or SP is perpendicular to QR
(b)
∠TSU = ∠USR = 1 u
∠PST = 1 u - 21°
1 u + 1 u + 1 u - 21° = 90° (Right angle)
3 u = 90° + 21° = 111°
1 u = 111° ÷ 3 = 37°
Answer(s): (a) PS or SP; (b) 37°