1 Answers
Option 2 : 70/3 cm2
⇒ Area of PBRQ is a square = 64
⇒ Side2 = 64
⇒ Side = 8 cm
⇒ PB = BR = RQ = QP = 8 cm
Now, in rectangle ABCD
⇒ CD = AB = AR + BR = 4 + 8 = 12 cm
⇒ AD = BC = CP + PB = 1 + 8 = 9 cm
In ΔARS and ΔCBA,
⇒ ∠A is common,
⇒ ∠R = ∠B = 90°
So, ΔARS and ΔCBA are similar,
⇒ AR ∶ AB = 4 ∶ 12 = 1 ∶ 3
⇒ SR ∶ CB = 1 ∶ 3
⇒ SR = (1/3) × 9 = 3 cm
⇒ QS = 5 cm
In ΔARS and ΔTQS,
⇒ ∠ASR = ∠TSQ (∵ vertically opposite angle)
⇒ ∠R = ∠Q = 90°
So, ΔARS and ΔTQS are similar
⇒ RS ∶ QS = 3 ∶ 5
⇒ AR ∶ QT = 3 ∶ 5
⇒ QT = (5/3) × 4 = 20/3 cm
⇒ TP = PQ – QT = 8 – (20/3) = 4/3 cm
⇒ Area of shaded region = Area of ΔARS + Area of ΔQST + Area of ΔTPC
⇒ Area of shaded region = {(1/2) × 3 × 4} + {(1/2) × 5 × (20/3)} + {(1/2) × (4/3) × 1} = 6 + (50/3) + (2/3) = 70/3
∴ Area of shaded region is (70/3) cm2