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Example 14 - Chapter 9 Class 7 Perimeter and Area
Last updated at April 16, 2024 by Teachoo
Area of combination of figures - two circles, circle and square
Chapter 9 Class 7 Perimeter and Area
Concept wise
- Basic Definitions
- Square and Rectangle
- Converting Square to Rectangle
- Area of parallelogram
- Area of triangle
- Circumference of circle
- Perimeter of a combination of shapes
- Area of circle
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Area of combination of figures - two circles, circle and square
- Finding Area of rectangle with path outside/inside
- Finding Area of rectangle with cross roads
- Finding Area of rectangle with triangle
Transcript
Example 14 The adjoining figure shows two circles with same centre. The radius of the larger circle is 10 cm and the radius of the smaller circle is 4 cm. Find: (a) the area of the larger circle Radius of larger circle = R = 10 cm Area of larger circle = 𝜋R2 = 3.14 × (10)2 = 3.14 × 100 = 314/100 × 100 = 314 cm2 ∴ Area of larger circle is 314 cm2 Example 14 (b) the area of the smaller circle Radius of smaller circle = r = 4 cm Area of smaller circle = 𝜋r2 = 3.1 (4)2 = 3.14 × 16 = 314/100 × 16 = 5024/100 = 50.24 cm2 ∴ Area of smaller circle is 50.24 cm2 Example 14 (c) the shaded area between the two circles. (π = 3.14) Shaded area = Area of larger circle − Area of smaller circle = 314 − 50.24 = 314 − 50.24/100 = (314 × 100 − 5024)/100 = (𝟑𝟏𝟒𝟎𝟎 − 𝟓𝟎𝟐𝟒)/𝟏𝟎𝟎 = 26376/100 = 263.76 cm2 ∴ Shaded area is 263.76 cm2
