## Book: RD Sharma - Mathematics

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

#### Subject: Maths - Class 8th

##### Q. No. 4 of Exercise 20.3

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##### Find the area of the following polygon, if AL = 10 cm, AM = 20 cm, AN = 50 cm. AO = 60 cm and AD = 90 cm.

AL = 10 cm; AM = 20 cm; AN = 50 cm; AO = 60 cm; AD = 90 cm given

LM = AM – AL = 20 – 10 = 10 cm

MN = AN – AM = 50 – 20 = 30 cm

OD = AD – AO = 90 – 60 = 30 cm

ON = AO – AN = 60 – 50 = 10 cm

DN = OD + ON = 30 + 10 = 40 cm

OM = MN + ON = 30 + 10 = 40 cm

LN = LM + MN = 10 + 30 = 40 cm

Area of given figure = area of triangle AMF + area of trapezium FMNE + area of triangle END + area of triangle ALB + area of trapezium LBCN + area of triangle DNC

Area of right angled triangle =

Area of trapezium =

Area of given hexagon =

Area of given hexagon =

Area of given hexagon = = 5050 cm2

Therefore area of given hexagon is 5050 cm2

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