RD Sharma - Mathematics

Book: RD Sharma - Mathematics

Chapter: 20. Mensuration-I (Area of a Trapezium and a Polygon)

Subject: Maths - Class 8th

Q. No. 2 of Exercise 20.3

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2

Find the area enclosed by each of the following figures [fig. 20.49 (i)-(ii)] as the sum of the areas of a rectangle and a trapezium.

Figure (i)


Area of given figure = Area of trapezium + area of rectangle


Area of given figure =


Area of given figure =


Area of given figure =


Therefore area of given figure is 424 cm2


Figure (ii)


Area of given figure = Area of trapezium + area of rectangle


Area of given figure =


Area of given figure =


Area of given figure =


Therefore area of given figure is 384 cm2


Figure (iii)


Using pythagorous theorem in the right angled triangle


52 = 42 + x2


x2 = 25 – 16


x2 = 9


x = 3 cm


Area of given figure = Area of trapezium + area of rectangle


Area of given figure =


Area of given figure =


Area of given figure =


Therefore area of given figure is 54 cm2


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