The first one is a parallelogram. The formula for the area of a parallelogram is:
[tex]a = bh[/tex]
When we plug the givens in:
[tex]a = 13 \times 9 \\ a = 117[/tex]
The answer to b. is 117 cm^2.
For the second one, a rectangular prism, we use:
[tex]a = 2(wl + hl + hw)[/tex]
Plug the values in:
[tex]a = 2(15 \times 20 + 8 \times 20 + 8 \times 15)[/tex]
Simplify:
[tex]a = 2(300 + 160 + 120) \\ a = 2 \times 580 = 1160[/tex]
The answer to 9a. is 1160 cm^2.
