the length of a large solid prism is 1.5 times the length of the small. face area of one prism is 100 cm square, find the face area of 2nd prism

Question

IGCSE mathematics. geometry

Answer 1

When comparing length (or perimeter) of one solid to another, just multiply by the scale factor (1.5 in this case).

When comparing area (remember it's measured in square units -- 2 dimensional)  multiply by scale factor squared.

When comparing volume (cubic units-- 3 dimensions) multiply by scale factor cubed.

 

1st prism    ---->               2nd prism

 

length              x 1.5

area                 x (1.5)²

volume             x (1.5)³

 

 

So, if length of 2nd prism is 1.5 times length of 1st prism, then AREA of 2nd prism is (1.5)² tiimes area of 1st prism.

 

100 x 2.25 = 225 cm²