length of pipe= 30m
Inside dia. = 1.2m
Outside dia. = 1.8m
Volume of concrete= (outside dia. - inside dia.)h
V= (pi)
v= [(3.14*0.9*0.9)-(3.14*0.6*0.6)]30
v= (3.3534-1.1304)30
v=(2.233)30 = 66.690m cube
since it's volume the answer 66.690 is in cubic meters.
For this case we have that by definition, the volume of a rectangular prism is given by:

Where:
It is the area of the base of the prism
h: It is the height

Where:
w: is the width
l: is the length
According to the data of the statement we have:

Substituting the data we have:

We choose the positive value: 
So the height is
Answer:

Answer: 2x-3=15
2(9)-3=15
18-3=15
It would be 23.5 idk if your aloud to do that
or 141/6