Ex 9.2, 3 - Chapter 9 Class 7 Perimeter and Area
Last updated at April 16, 2024 by Teachoo
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
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Area of circle
- 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
Ex 9.2, 3 If the circumference of a circular sheet is 154 m, find its radius. Also find the area of the sheet. (𝑇𝑎𝑘𝑒 𝜋=22/7) Radius = r = ? Given, Circumference = 154 m 2𝜋r = 154 2 × 22/7 × r = 154 (2 × 22)/7 × r = 154 r = 154 × 𝟕/(𝟐 × 𝟐𝟐) r = 77 × 7/22 r = 7 × 7/2 r = 49/2 r = 24.5 m Now, Area of circle = 𝜋r2 = 𝟐𝟐/𝟕 × (𝟐𝟒.𝟓)^𝟐 = 22/7 × (49/2)^2 = 𝟐𝟐/𝟕 × 𝟒𝟗/𝟐 × 𝟒𝟗/𝟐 = 11/7 × 49 × 49/2 = 11 × 7 × 49/2 = 11 × 343/2 = 𝟑𝟕𝟕𝟑/𝟐 = 1886.5 m2 Therefore, Radius of circular sheet is 24.5 m & Area of circular sheet is 1886.5 m2
