I believe that a rectangular prism since (hence the name) it's made up of rectangles, only with 2 squares helping to close it up.
Answer:
b=16
Step-by-step explanation:
Formula~ 1/2*b*h
1/2*15*b=120
7.5b=120
b=120/7.5
b=16
(you can substitute the value to check-i've done it below)
1/2*16*15=?
if you work it out, the ans will be 120, therefore the ans is correct!
Completing the square gives


At the point on the graph along the axis of symmetry, the squared term vanishes, so that when
, we have
. So
