If the volume for 3-d polyhedra a is 400 cm3 and the volume for 3-d polyhedral b is 800 cm3. how many times bigger is the volume of pyramid b than pyramid a? 200% 20% 2% 0.2%

For this case we can make the following rule of three:
 400 cm ^ 3 ---------------> 100%
 800 cm ^ 3 --------------> x
 From here, we clear the value of x.
 We have then:
  
 the volume of pyramid B is 200% bigger than pyramid A