Question

08 Find the cost of polishing a circular table top of diameter 7m,if the rate of
polishing is Rs. 15 per m'. in 2 marks​

Answer 1

Solution :-

Here,

The polishing surface = Area of circular table

The diameter of the table = 7m

Therefore,

Radius of the table = Diameter / 2

Radius = 7/2m

Now,

As we know that,

Area of circle = πr^2

Therefore,

The area of a circular table top = πr^2

Area of a circular table top

= 22/7 * 7/2 * 7/2

= 11 * 7/2

= 77/2

= 38.5m^2

Now,

The cost of polishing per m^2 = Rs 15

Therefore,

The cost of polishing 38.5m^2

= 15 * 38.5 = Rs 577.5

Hence, The cost of polishing the table top is Rs 577.5 $.$

Answer 2

Given

• Diameter of circular table top = 7 m
• Rate of polishing = Rs 15 per m²

To find

• Cost of polishing the circular table top

Solution

Since, the circular table top will be in the shape of circle, let's find out the area of circle.

• Area of circle = πr²

Where :-

• π = 22/7
• r = radius

We have,

• Diameter = 7 m
• Radius = Diameter/2
• Radius = 7/2
• Radius = 3.5 m

Substituting we get :-

• πr²
• 22/7 × 3.5 × 3.5
• 22/7 × 35/10 × 35/10
• 22/7 × 12.25
• 38.5

Hence, the area of circle is 38.5 m²

Now :-

• Rs 15 - m²
• Rs x - 38.5 m²
• Rs x - 38.5 × 15
• Rs x - 577.5

Hence, the cost of polishing the circular table top is Rs 577.5 /-