Answer:
Volume of composite is 483   
 
Step-by-step explanation:
We need to add the volume of a rectangular prism (7 mm x 12 mm x 3 mm) to a semi-cylinder (of radius 3.5 mm and height 12 mm):
Volume of the prism = 7 x 12 x 3  = 252
  = 252  
 
Volume of the semi-cylinder =  
Therefore the sum of both volumes gives:
(252 + 230.907)  = 482.907
 = 482.907   
 
WHich can be rounded to the nearest whole number as: 483 