## Book: RD Sharma - Mathematics

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

#### Subject: Maths - Class 8th

##### Q. No. 1 of Exercise 20.2

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##### Find the area, in square metres, of the trapezium whose bases and altitudes are as under:(i) bases = 12 dm and 20 dm, altitude = 10 dm(ii) bases = 28 cm and 3 dm, altitude = 25 cm(iii) bases = 8 m and 60 dm, altitude = 40 dm(iv) bases = 150 cm and 30 dm, altitude = 9 dm

(i) Area of trapezium =

Length of bases of trapezium = 12 dm and 20 dm

10 dm = 1 m

Therefore length of bases in m = 1.2 m and 2 m

Similarly length of altitude in m = 1 m

Area of trapezium =

Area of trapezium = m2

(ii) Area of trapezium =

Length of bases of trapezium = 28 cm and 3 dm

10 dm = 1 m

Therefore length of bases in m = 0.28 m and 0.3 m

Similarly length of altitude in m = 0.25 m

Area of trapezium =

Area of trapezium = m2

(iii) Area of trapezium =

Length of bases of trapezium = 8 m and 60 dm

10 dm = 1 m

Therefore length of bases in m = 8 m and 6 m

Similarly length of altitude in m = 4 m

Area of trapezium =

Area of trapezium = m2

(iv) Area of trapezium =

Length of bases of trapezium = 150 cm and 30 dm

10 dm = 1 m

Therefore length of bases in m = 1.5 m and 3 m

Similarly length of altitude in m = 0.9 m

Area of trapezium =

Area of trapezium = m2

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