ABCD is a quadrant of a circle of radius 28 cm And a semicircle BEC is drawn with BC as diameter find the area of the shaded region
Answers
ABCD is a quadrent of a circle of radius 28cm, and a semicircle BEC is drawn with BC as diameter. The area of the shaded region is 392 cm².
Stepwise explanation is given below:
- It is given that,
radius of the circle = AB = AC = 28 cm
- Area of quadrant ABDC = 1/4×π×r²
= (1/4×22/7×28×28) cm²
=22× 28= 616 cm²
- Area of ∆ABC = 1/2×AC×AB = (1/2×28×28)
= 392 cm²
- Area of segment BDC = Area of quadrant ABDC − Area of ∆ABC
= (616− 392) cm²
= 224 cm² .............(1)
- In a right angled ∆ BAC
BC² = BA²+ AC² (By Pythagoras theorem)
BC² = (28²+ 28²) cm²
BC²= 784 +784 cm²
BC = √16×98 = √ 16 × 49 ×2
BC = 4×7√2= 28√2
BC= 28√2 cm
- radius of semicircle= 28√2/2= 14√2 cm
Area of semicircle BEC= 1/2×π×r²
= ( 1/2×22/7×14√2×14√2) cm²
= 22 × √2 × 14√2 = 22×14×2 = 44 ×14
= 616 cm²
- Area of the shaded portion = Area of semicircle BEC − Area of segment BPC
= 616 − 224 cm²= 392 cm²
- Hence, the area of the shaded region = 392 cm².