7th Class
Mathematics
Mensuration
Question Bank
Mensuration
question_answer
A playground is in the form of a rectangle having semicircle on the shorter sides. Find its area when the length of the rectangular portion is 80 m and the breadth is 42 m.
A) \[4746\,{{m}^{2}}\]
B) \[4748\,{{m}^{2}}\]
C) \[4950\,{{m}^{2}}\]
D) \[5049\,{{m}^{2}}\]
Correct Answer:
A
Solution :
Radius of each of semi-circle \[=\frac{42}{2}=21\,m\] The required area = 2\[\times \]area of semi-circle EFA + area of rectangle ABDE \[=2\times \frac{1}{2}\pi {{(21)}^{2}}+80\times 42\] \[=\frac{22}{7}\times 21\times 21+80\times 42=4746\,{{m}^{2}}.\]