20 POINTS!! M is directly proportional to r squared when r=2, m=14
Workout the value of r when M =224

r = 8

Step-by-step explanation:

Given that M is directly proportional to r² then the equation relating them is

M = kr² ← k is the constant of proportionality

To find k use the condition when r = 2 , M = 14

k = =  =

M = r² ← equation of proportion

When M = 224, then

224 =r² ← multiply both sides by 2

7r² = 448 ( divide both sides by 7 )

r² = 64 ( take the square root of both sides )

r = = 8

have wonderful day