Find the area of the shaded region in Fig 9.50

Solution:

Consider r as the radius of smaller circle and R as the radius of bigger circle

From the figure, we can see,

r = 7/2 = 3.5 cm

R = 7/2 + 7 = 21/2 = 10.5 cm

We know that

Area of shaded region = Area of bigger circle - Area of smaller circle

= πR² - πr²

Taking π as common

= π (R² - r²)

Substituting the values

= π[(10.5)² - (3.5)²]

By further calculation

= π (110.25 - 12.25)

So we get

= 22/7 × 98

= 308 cm²

Therefore, the area of the shaded region is 308 cm².

✦ Try This: Find the area of a circle with radius 4.5 cm.

☛ Also Check: NCERT Solutions for Class 7 Maths Chapter 11

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NCERT Exemplar Class 7 Maths Chapter 9 Problem 98

Find the area of the shaded region in Fig 9.50

Summary:

The area of the shaded region is 308 cm²

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☛ Related Questions:

• Find the area of the shaded region in Fig 9.51
• A circle with radius 16 cm is cut into four equal parts and rearranged to form another shape as show . . . .
• A large square is made by arranging a small square surrounded by four congruent rectangles as shown . . . .