7 cm
8 cm
(b)find the area of the shaded
Answers
Answer: Area of big cirlcle -( area of semi circle1 + area of semi circle2)
Step-by-step explanation:
πR² - (πr1/2 + πr2/2)
22/7×15/2-(22/7×7/4 + 22/7×2)
11/7×15 -( 11/2 + 44/7)
165/7 - ( 77/14 + 88/14)
165/7 - ( 165/14)
330/14-165/14
165/14 = 11.78 cm²
Answer:
Area of shaded region = 132 + 11/28 cm²
Step-by-step explanation:
Diameter of the big circle = (8 + 7) cm = 15 cm
Area of big circle = 22/7 × 15/2 × 15/2 cm²
= 22/7 × 225/4 cm²
= 11/7 × 225/2 cm²
Area of semicircle with diameter 7 cm = 1/2 × 22/7 × 7/2 × 7/2 cm²
= 11/7 × 49/4 cm²
Area of semicircle with diameter 8 cm = 1/2 × 22/7 × 8/2 × 8/2 cm²
= 11/7 × 64/4 cm²
Area of shaded region = 11/7 ( 225/2 - 49/4 - 64/4) cm²
= 11/7 (450 - 49 - 64)/4 cm²
= 11/28 × 337 cm²
= 132 + 11/28 cm²
Formula used :
Area of circle = πr² = 22r²/7 sq. units
Area of semicircle = πr²/2 = 22r²/14 = 11r²/7 sq. units