RD Sharma - Mathematics

Book: RD Sharma - Mathematics

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

Subject: Maths - Class 8th

Q. No. 13 of Exercise 20.1

Listen NCERT Audio Books to boost your productivity and retention power by 2X.

13

A rectangular grassy plot is 112 m long and 78 m broad. It has gravel path 2.5 m wide all around it on the side. Find the area of the path and the cost of constructing it at Rs. 4.50 per square metre.

Inner area of rectangle = length× breadth


Inner area of rectangle = 112× 78 = 8736 m2


Width of path = 2.5 m


Length of outer rectangle = 112 +2.5 + 2.5 = 117 m


Breadth of outer rectangle = 78 +2.5 + 2.5 = 83 m


Outer area of rectangle = length× breadth


Outer area of rectangle = 117 × 83


Outer area of rectangle = 9711 m2


Area of path = outer area of rectangle – inner area of rectangle


Area of path = 9711 – 8736 = 975 m2


Chapter Exercises

More Exercise Questions