Direct Proportion
If y = kx, doubling x doubles y
Inverse Proportion
If y = k/x, doubling x halves y
Squared Proportion
If y = kx², doubling x quadruples y
Inverse Square
If y = k/x², doubling x reduces y to 1/4
Identify from Formulas
Look at how variables appear (numerator vs denominator, exponents)
Key Tip
“What happens to Y when X changes?” — the most common MCAT question pattern