Answer:
$5
Step-by-step explanation:
Cost per slice
3.75 / 3 = 1.25
Cost of 4 slices
1.25 * 4 = 5
To find AB(x) and BC(y), you can do(there are multiple ways you can do this):
tan A = 
tan 60° =
or (tan 60°) · 7 = y
tan 60° = 
√3 · 7 = y
7√3 cm = y
sin B = 
sin 30° =
or 
sin 30° =
= 
x = 
x = 14 cm
AB = 14cm
BC = 7√3 cm
10 quarts = 2.5 gallons.
There are 4 quarts for every 1 gallon, but because you're finding gallons and not quarts, you do 10 ÷ 4 = 2.5.