English, asked by jyotialbumphotobook, 4 months ago

a well of diameter 150 cm has 30 cm wide parapet running around it find the area of the parapet

Answers

Answered by MrPhantom
5

★ Given:-

The diameter of the well is 150cm.

The well has a 30 cm wide parapet running around it.

★ Solution:-

Diameter of well = 150 cm

Therefore, Radius of well = Diameter÷2 =

	 \frac{150}{2} =75cm

Width of parapet = 30 cm

Now, the parapet of the well forms two circles.

One is the inner circle and the second one is outer circle.

★ Here:-

Radius of the inner circle = 75 cm

So, radius of outer circle = radius of inner circle + width of parapet

= (75 + 30) cm = 105 cm

We know,

Area of parapet = Area of the outer circle - Area of the inner circle

Therefore, area of the parapet =  πR ^{2}  − πr ^{2}

= π(R ^{2} −r ^{2}  )

Therefore, a ^{2}  - b ^{2}

 = (a+b)(a−b)∣

   \frac{22}{7} (105+75)(105−75)

= \frac{22}{7}  \times 180 \times 30

=   \frac{118800}{7} cm ^{2}

=16971.428 \: cm ^{2}

Attachments:
Similar questions