Help !!!suppose r varies directly as the square of m

Question

Suppose r varies directly as the square of​ m, and inversely as s. If r=17 when m=6 and s=4​, find r when m=18 and s=4.

Answer 1

Combined Variation – both direct and indirect variation

Equation

y=k(x/z), k is the constant of variation, k cannot = 0

When r=17, m=6 and s=4, k = ?

r = k(m²/s)

17 = k(6²/4)

17 = k(36/4)

17 = 9k

17/9 = k

k = 17/9

Find r when m=18 and s=4, k=17/9

r = 17/9 * 18²/4

r = 17/9 * 324/4

r = 17/9 * 81

r = (17 * 81)/9

r = 1,377/9

r = 153

Answer

r = 153