Question

If a varies directly as the square of b, and a=5 when b=2, find a when b=3

Answer 1

a=5

b=2

then if

a=?

b=3

since

a varies directly as the square of b

`a\rightarrow b^2`

then

`5\rightarrow2^2`
`a\rightarrow3^2`

then

`a=(3^2*5)/(2^2)`
`a=(45)/(4)=11.25`

then

a=11.25