Need help on numbers 1 and 2 ill mark brainliest if they are right

Question author, it's spelled pi not pie, and we use just use the Greek letter π.  Students, demand better from your teachers.

1. Rectangular prism, aka a box. Volume is length times width times height.

V = 5×7×9 = 315 cubic feet

That's cubic feet of course, the product of three lengths.  We didn't even need to do the problem, just look for the common answer and pick the one with the right units.  I just saw that same pattern in a volume problem yesterday.

315 cubic feet, first choice

2. Cylinder, volume is base area times height, πr²h.   We have a radius of r=14/2=7 yd and h=8 yd.  We're using π=3.14.

V = πr²h = 3.14(7²)(8) = 1230.88 cubic yds

1230.9 cubic yards, last choice

b.an increase in a causes b to decrease

$450 is the answer.

step-by-step explanation:

30% of 450 = 135

450-135=315