how do I get the correct answer?

Answer:
1989.674m³
Step-by-step explanation:
It’s difficult to see the picture, and I can’t read the question. Are you looking for the volume of the composite shape? If so:
Cylinder: V=[tex]\pi[/tex]r²h =
Cone: V=[tex]\pi[/tex]r²h/3 =
Hemisphere: V=2/3[tex]\pi[/tex]r³ = 2/3
TOTAL: 1570.796+157.079+261.799=1989.674m³