# 35 cm 40 cm Area of rectangle = length × breadth Area of cardboard = 40 cm × 35 cm = 1400 cm² Area of picture = 30 cm × 25 cm = 750 cm² Area of cardboard.

## Presentation on theme: "35 cm 40 cm Area of rectangle = length × breadth Area of cardboard = 40 cm × 35 cm = 1400 cm² Area of picture = 30 cm × 25 cm = 750 cm² Area of cardboard."— Presentation transcript:

35 cm 40 cm Area of rectangle = length × breadth Area of cardboard = 40 cm × 35 cm = 1400 cm² Area of picture = 30 cm × 25 cm = 750 cm² Area of cardboard not covered by the picture = 1400 cm² - 750 cm² = 650 cm² 25 cm 30 cm 1.A picture 30 cm by 25 cm is mounted on a cardboard 40 cm by 35 cm. Find the area of the cardboard not covered by the picture.

6 cm 4 cm C M A 2 cm 8 cm C B A 2.Find the area of the shaded part of the isosceles triangle ABC of height 6 cm and base 8 cm. The length of each side of the square is 2 cm. Area of triangle = ½ × base × height Area of triangle AMC= ½ × 4 cm × 6 cm = 12 cm² Area of triangle ABC = 2 × 12 (isosceles triangle) = 24 cm² Area of square = length × length = 2 cm × 2 cm = 4 cm² Area of shaded part of the isosceles triangle = area of triangle ABC – area of square = 24 cm² - 4 cm² = 20 cm² 6 cm

3.Find the area of the shaded portion. ( π = 22 / 7 ) Area of square= length × length = 14 cm × 14 cm = 196 cm² radius of circle = 14 / 2 = 7 cm Area of ½ a circle = ½πr² = ½ × 22 / 7 × 7 cm × 7 cm = 77 cm² Area of the shaded portion = area of square – area of ½ a circle = 196 cm² - 77 cm² = 119 cm² 14 cm

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