Question

a circular park of radius 20m has a 5m wide road running around it. Find the cost of metalling the road at the rate of 18.90 per sq m​

Answer 1

Answer ::

The cost of metalling the road at the rate of 18.90 per m² is Rs. 13364.946.

Step-by-step explanation ::

To Find :-

• The cost of metalling the road at the rate of 18.90 per m²

Solution :-

Given that,

• A circular park of radius 20m has a 5m wide road running around it.
• We need to find out the cost of metalling the road at the rate of 18.90 per m²

Figure :-

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Let us assume the radius of outer circle and the radius of inner circle as a R and r respectively.

According the question,

First we need to find out the radius of outer circle,

= 20m + 5m

= 25m

The radius of outer circle is 25m.

Now, let's find out the area of the road, As the whole circle forms a hollow circle, so we can get the area of road, by

Area of road = Area of outer circle - Area of inner circle,

As we know that,

Area of circle = πr², therefore,

» πR² - πr²

» π ( 25² - 20² )

» π ( 625 - 400 )

» π ( 225 )

» 22/7 × 225

» 4950/7

» 707.14

The area of the road is 707.14m²≈.

Now let's find out the cost of metalling the road at the rate of 18.90 per m²,

» Rs. ( 707.14 × 18.90 )

» Rs. 13364.946

The cost of metalling the road at the rate of 18.90 per m² is 13364.946.