To find the total volume of the box, you will find the volumes of each separate piece.
Use the formulas for finding the volumes of each:
V = 1/3 Bh (pyramid); B stands for the area of the base shape
1/3 x 8 x 8 x 3
V = 64 cubic inches
V = Bh (prism)
8 x 8 x 4
V = 256 cubic inches
256 + 64 = 320 cubic inches
The total volume of the box is 320 cubic inches.
-8
2/3(-21/3) + 2/3(-15/3)
-42/9 + -30/9
-72/9 = -8
Round each number to the nearest 10.
33 rounds to 30 and 89 rounds to 90, thus in your head it's easier to mentally add 30 + 90 for purposes of estimation.
First subtract the C to move it to the other side
c-P=b+4a
Then subtract the 4a as well
4a-c-p=b