Question

Somebody please help! Marked Brainliest!

Answer 1

Answer:

Part A:

The surface area of a cylinder is given by

A=  6πr² if h= 2r

Part B:

Total Cost of covering the cylinder = Rate *2πrh + rate*2πr²

Cost of covering only the side = Rate *2πrh

Step-by-step explanation:

Part A:

The surface area of a cylinder is given by

A= 2πrh + 2πr²

Where h= height and radius = r

But we have the height twice as radius so h= 2r

So putting h= 2r we get

A= 2πr(2r) + 2πr²

A= 4πr² + 2πr²= 2πr²(2+1) = 2πr²(3)= 6πr²

Part B:

Cost = Rate * area of the wall + rate * area of the top and bottom

Cost = Rate *2πrh + rate*2πr²

Where area of the top and bottom= πr² +πr² =2 πr²

and area of the side = 2πrh

Multiplying both with the rate and then adding would give the total cost of materials needed to cover the outside of the cylinder and from top and bottom as well.

If  you do not need to cover top and bottom then the expression would be

Cost of covering only the side = Rate *2πrh

Part C:

Already done above.