Answer:
r = 6
Step-by-step explanation:
Given that p varies directly as r, then the equation relating them is
p = kr ← k is the constant of variation
To find k use the condition p = 4, r = 2
k = [tex]\frac{p}{r}[/tex] = [tex]\frac{4}{2}[/tex] = 2
p = 2r ← equation of variation
When p = 12
12 = 2r ( divide both sides by 2 )
hence r = 6
