Answer:
Answer: B) initial height = 150; hits the ground between 5 and 6 seconds
Perimeter is the sum of all the sides. So we can set up an equation:

Now solve for 'x', combine like terms:
When it comes to terms with variables it's just like normal addition but we keep the variable:


So we have:

Add:

Subtract 7x to both sides:

Subtract 4 to both sides:

Divide 5 to both sides:
We know all the side lengths so can use law of cosines. a=90, b=55, and c=50.
2500=8100+3025-2(90)(55)cos(C)
cos(C)=.8712
C=arccos(.8712)=29.4 degrees
Length of each side of cube is =

SO the volume of cube =

=

=

=

SO the volume of cube is