Answer:
1. 2 cups
2. 0.5.
Hope this helps!
Step-by-step explanation:
The two parabolas intersect for

and so the base of each solid is the set

The side length of each cross section that coincides with B is equal to the vertical distance between the two parabolas,
. But since -2 ≤ x ≤ 2, this reduces to
.
a. Square cross sections will contribute a volume of

where ∆x is the thickness of the section. Then the volume would be

where we take advantage of symmetry in the first line.
b. For a semicircle, the side length we found earlier corresponds to diameter. Each semicircular cross section will contribute a volume of

We end up with the same integral as before except for the leading constant:

Using the result of part (a), the volume is

c. An equilateral triangle with side length s has area √3/4 s², hence the volume of a given section is

and using the result of part (a) again, the volume is

Area of rectangular post card = length x width
For the given post card:
length = 4 in
width = (3+b) in
area = 24 in^2
So, substituting in the equation of the area:
24 = 4 x (3+b)
24 = 12 + 4b
24 - 12 = 4b
12 = 4b
b = 3 in
Therefore:
the length of the postcard = 4 inch
the width of the postcard = b+3 = 3 + 3 = 6 inch
12/10 = 1 2/10 or 1 1/5
15/6 = 2 3/6 or 2 1/2.
To turn these fractions into mixed numbers you have to see how much times the denominator can go into the numerator and the amount of numbers left over. For 12/10, 10 can go into 12 1 time, so the whole number is 1. There is 2 numbers left over, so the numerator is 2 and you do not have to change the denominator. To simplify, divide the numerator and denominator by the highest number it can be divided to