I am having trouble answering these three problems on my homework. Hoping someone would be able to help me out thanks so much. I struggle with these kinds of problems on math home work . .

Question

I am having trouble answering these three problems on my homework. Hoping someone would be able to help I am completely stuck

1-

In order to prepare a piece of ground for building a brick patio, a rectangle mesauring 8 by 10 feet must be marked off. Then dirt within the rectangle must be dug out to a depth of 6 inches. Finally resulting space must be filled with sand.

A) What is the volume of sand needed, in cubic feet to fill the space?

The kid put 80 cubic feet (8x10=80)

B) Sand costs $4 per cubic foot. What is the total cost of the sand needed to fill this space, including a $35 delivery charge?

The student put total of $335 (80x4=325+35=335)

Is the student correct or incorrect?

2- Find the area of the red shaded part. The large circle has a diameter of 64cm. Give answer in both terms of pi and then round your final answer to one decimal place.

Area of red shaded parts in term of pi=

Area of red shaded part rounded to one decimal place=

3- A box is packed with 12 rolls of toilet paper. Each roll has a height and a diameter of 5 inches. The cardboard tube on the inside has a diameter of 1.6 inches. What percent of the box is occupied by air? Solve each of the following and show all work,. Only round the final percent answer to two decimal places. Leave all other answers in terms of pi.

Volume of box= ____ in^3

Find the volume of 1 roll of toilet paper. Make sure to subtract the air inside the roll

Find the volume of 12 rolls of toilet paper

Find the volume of the air

What percentage of the box is occupied by air? Round to 2 decimal places

EDIT I was able to solve #3 and #2 I believe. I need help mostly with #1

Answer 1

formula for volume of rectangle (V)= length x width x height

6 inches x 1ft/12inches = 0.5 ft

V = 8ft x 10ft x 0.5ft = 40 ft^3

need 40 ft^3 of sand to fill the sand box

total cost of the sand

4 $/ft^3 x 40 ft^3 = $160.00