Answer:
4.24m³
Step-by-step explanation:
The inside diameter of 1.2 m of the pipe
Radius of the inside pipe = Diameter/2 = 1.2/2 = 0.6m
The outside diameter of 1.8 m
Radius of the outer of the pipe = 1.8/2 = 0.9m
Height of the pipe = 3.0m
A Pipe looks like the shape of the cylinder. Hence,
Volume of concrete in the pipe = Volume of the outer section of the Pipe - Volume of the inner section of the pipe
Volume of the outer section of the Pipe = πr²h
h = 3.0m
r = 0.9
= π × 0.9² × 3.0
= 7.63m³
Volume of the inner section of the Pipe = πr²h
h = 3.0m
r = 0.6
= π × 0.6² × 3.0
= 3.39m³
Volume of concrete in the pipe = Volume of the outer section of the Pipe - Volume of the inner section of the pipe
= 7.63m³ - 3.39m³
= 4.24m³
Therefore, volume of concrete in the pipe is 4.24m³
is the boundary of the triangle 
, then by Green's theorem
