Question

Direct Variation Solve using proportional reasoning. y is directly proportional to x, and y = 216 when x = = 2. a. Find y when x = 7 b. Find x when y = 540

Answer 1

Answer:

a) y = 756

b) x = 5

Explanations:

y is directly proportional to x

y α x

y = kx

y = 216 when x = 2

Substitute the values of x and y into the equation y = kx to get the constant of proportionality, k.

y = kx

216 = k x 2

k = 216 / 2

k = 108

y = 108x

a) Find y when x = 7

y = 108x

y = 108(7)

y = 756

b) Find x when y = 540

y = 108x

540 = 108x

x = 540/108

x = 5