Question

Aval of diameter 150 cm has a 30 cm wide parapet running out it find the area of the parapet

Answer 1

Answer:

heya mate✌

Diameter of well = 150 cm

Radius of well = \displaystyle \frac{150}{2} = 75 cm2150=75cm

Width of parapet = 30 cm

Now, parapet of the well forms two circles.

One is inner circle and second is outer circle.

Radius of inner circle r = 75 cm

Radius of outer circle = inner radius + width of parapet = 75 + 30 = 105 cm

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

= \pi R^2 - \pi r^2 = \pi (R^2 - r^2)πR2−πr2=π(R2−r2)

= \displaystyle \frac{22}{7} |(105)^2 - (75)^2|722∣(105)2−(75)2∣               

                                                   | \therefore a^2 - b^2 = (a + b) (a - b)|∣∴a2−b2=(a+b)(a−b)∣

= \displaystyle \frac{22}{7} (105+ 75) (105 - 75)722(105+75)(105−75)

= \displaystyle \frac{22}{7} \times 180 \times 30722×180×30

= \displaystyle \frac{118800}{7} cm^2 = 16971.428 cm^27118800cm2=16971.428cm2....hope it hlps❣

Answer 2

Answer:

16971.428 cm2

Step-by-step explanation:

hope it is useful