Question

If y = 7.2 when x = 10, what is the value of x when y = 20? (y varies inversely as the square of x.) A. 14.4 B. 10 C. 6 D. 20

Answer 1

Answer:

6

Step-by-step explanation:

Y is directly proportional to 1/x2

Y = k/x2

Where k is the proportionality constant

y1*(x1)2 = y2*(x2)2

7.2*(10)2 = 20*(x2)2

x2 = sqrt(36)

X = 6