Question

A circular pond had the radius 70m. 7m wide foothpath runs around it find the area of the foothpath. what will be the cost of leveling the foothpath at $ 15per sq m? ​

Answer 1

$\huge\color{cyan}\boxed{\colorbox{black}{☛Solution࿐}}$

GIVEN :-

Radius of circular pond ( r ) = 70 m.

Width of footpath ( w ) = 7 m.

TO FIND :-

The area of footpath.

SOLUTION :-

Let the radius of circular pond be "r" and the radius of outer circle ( bigger circle ) be "R".

➳ R = r + w

➳ R = 70m + 7m

➳ R = 77m.

Now,

➳ Area of footpath = πR² - πr²

➳ Area of footpath = 22/7 × (77)² - 22/7 × (70)²

➳ Area of footpath = 22 × 77 × 11 - 22 × 70 × 10

➳ Area of footpath = 18634 - 15400

➳ Area of footpath = 3234m²

Now,

➳ Total cost of levelling = Area × Rate

➳ Total cost of levelling = 3234 × 15

➳ Total cost of levelling = Rs. 48510

Hence Total cost of levelling the footpath = Rs. 48510.

HOPE SO IT HELPS YOU

Answer 2

Step-by-step explanation:

GIVEN :-

Radius of circular pond ( r ) = 70 m.

Width of footpath ( w ) = 7 m.

TO FIND :-

The area of footpath.

SOLUTION :-

Let the radius of circular pond be "r" and the radius of outer circle ( bigger circle ) be "R".

➳ R = r + w

➳ R = 70m + 7m

➳ R = 77m.

Now,

➳ Area of footpath = πR² - πr²

➳ Area of footpath = 22/7 × (77)² - 22/7 × (70)²

➳ Area of footpath = 22 × 77 × 11 - 22 × 70 × 10

➳ Area of footpath = 18634 - 15400

➳ Area of footpath = 3234m²

Now,

➳ Total cost of levelling = Area × Rate

➳ Total cost of levelling = 3234 × 15

➳ Total cost of levelling = Rs. 48510

Hence Total cost of levelling the footpath = Rs. 48510.