For 3 find the total area for the big semicircle, then find the area of the smaller one and subtract it. It would be the same for 4 but instead you find the total area of the square (24 x 24) and then subtract the semicircle are. (you were wrong on #4)
The surface area is the area of one of the cube's faces. The volume, however is how much of something could fit inside of the cube.
One gallon costs $1.88. To find the cost of seven gallons, you would multiply this price by seven.
1.88 x 7 = $13.16, which is answer D
