Sagot :
A. Direct Variation- there is a direct variation when a situation produces pairs of numbers in which their ratio is constant.
B. Inverse Variation- occurs when a situation produces pairs of numbers and there is constant.
C. Joint Variation- occurs when a varies jointly as b and c means a=kbc or k=a/bc where k is the constant of variation.
D. Combined Variation- occurs when a varies directly as b and inversely as c means a=kb