Algebra II Recipe: Variation

By G Redden

A. Definitions

Direct Variation - x and y show direct variation if y = kx and k ≠ 0.
Inverse Variation - x and y show inverse variation if y = (k/x) and k ≠ 0.
Joint Variation - z varies jointly with x and y if z = kxy and k ≠ 0.

Directions and/or Common Information:

Write an equation for the given relationship.

b varies directly with a.

b varies inversely with a.

c varies jointly with a and b.

b varies inversely with the cube of a.

c varies directly with a and inversely with b.

Practice Problems