Question

21. The diameter of a circular park is 42 m. A 3.5 m wide path runs around it from inside. Find the cost of paving for path at Rs 2 per sq.m. ​

Answer 1

$Radius = \frac{42}{2} \\ = 21$

$Internal \: Radius = 21 \: m$

$External \: Radius \\ = 21 +3.5 \\ =24.5 m$

$Area \: of \: Path = \pi( {24.5)}^{2} - \pi {(21)}^{2}$

$= \pi( {24.5}^{2} - {21}^{2} )$

$= 500.5$

$Cost \: of \: Travelling \\ = 500.5 \times 2 \\ = Rs \: 1,001$

Answer 2

Answer:

Correct option is A)

Internal Radius = 21 m, External Radius =21+3.5=24.5 m

Area of path = π(24.5)

2

−π(21)

2

⇒π[(24.5)

2

−(21)

2

]

=500.5

Cost of travelling =500.5×4=Rs.2002