10th Class
Mathematics
Areas Related to Circles
Question Bank
Areas Related to Circles
question_answer
A square water tank has its sides equal to 40 m. There are four semicircular grassy plots all round it. Find the cost of turfing the plots at \[Rs.\text{ }1.25\]per sq. m.
A) Rs.2671
B) Rs.4401
C) Rs.2512
D) Rs.3140
Correct Answer:
D
Solution :
\[AB=40\text{ }m\] and radius of semicircular plot \[=\frac{40}{2}=20\,m\] Area of 4 circular plots \[=4\times \] (Area of semi circle) \[=4\times \frac{1}{2}\times \pi \times {{20}^{2}}\] \[=2\times 3.14\times 400=2512\,{{m}^{2}}\] Cost of turfing the plots at the rate Rs.1.25 per sq. \[m=2512\times 1.25=Rs.3140\]