Question

find the cost of polishing a circular table top of diameter 14m if the rate of polishing is rs.10/m​

Answer 1

Appropriate Question:

Find the cost of polishing a circular table top of diameter 14 m if the rate of polishing is Rs 10 per sq. metre.

Required Solution :

Given:

• Diameter or the circular table = 14 m

• Rate of polishing per sq. metre = Rs. 10

To calculate:

• Cost of polishing a circular table top.

Calculation:

In order to calculate cost of polishing a circular table top, we have to calculate area of the circular table top first.

We know that,

★$\boxed{\sf{ Diameter = 2 \times Radius}}$

$\sf{\longrightarrow Radius = \dfrac{14}{2}}$

( Since diameter is 14 m. )

$\sf \red{\longrightarrow Radius = 7 \: m}$

Also, we know that :

★$\boxed{\sf{ {Area}_{(Circle)} =\pi {r}^{2} }}$

Inserting values:

$\sf{\longrightarrow {Area}_{(Circle)} =\dfrac{22}{7} \times {7}^{2} \: {m}^{2} }$

$\sf{\longrightarrow {Area}_{(Circle)} =\dfrac{22}{7} \times 49 \: {m}^{2} }$

$\sf{\longrightarrow {Area}_{(Circle)} = 22 \times 7 \: {m}^{2} }$

$\sf \red{\longrightarrow {Area}_{(Circle)} = 154 \: {m}^{2} }$

Now, as per the given question:

→ Rate of polishing per sq. metre = Rs. 10

Therefore, rate of polishing a circular table top :-

$\sf {\longrightarrow Rs. ( 154 \times 10)}$

$\sf \red {\longrightarrow Rs. \: 1540}$

Therefore, cost of polishing a circular table top is Rs 1540.