Question

A circular well is dug. Its diameter is 3 1/2m and its depth is 6 m. What is the lateral surface area of the well? What is the volume of the earth removed to make the well?​

Answer 1

Answer:

diameter=3.5 m

r=1.75

h=6 m

lateral surface area of a cylinder=2πrh=65.97 m

volume=πr²h=57.73 m³

so 57.73 m³ soil will remove

Answer 2

Step-by-step explanation:

The surface area in this case will be the curved surface area of the well+ area of the base.

D= 3 1/2 m

= 7/2 m

r= 7/2/2 = 7/4 m

depth (h)= 6m

Surface area= 2πrh + πr²

= πr(2h+r)

= 22/7 × 7/4 m ( 2×6m +7/4 m)

= 11/2 m (12m+ 7/4 m)

= 11/2 m ( 48m+7m)/4

= 11m(55m)/8

= 605m²/8

= 75.625 m²

Volume of the earth removed= vol³ of the well

= πr²h

= 22/7 × 7/4 m× 7/4 m× 6m

= 11×1m×7m×3m/4

= 77m²×3m/4

= 231m³/4

= 57.75 m³

Sorry, the question says lateral surface area

= 2πrh

= 2×22/7 × 7/4 m ×6m

= 11×1m×6m

= 66m².