Y is inversely proportional to x squared. given that y = 2.5 when x = 24.

1. find an expression for y in terms of x y

2. find the value of y when x=20

3. find the value of x when y=16

If y is inversely proportional to x^2 ...

y=k/x^2, we are given that y=2.5 and x=24 so

2.5=k/24^2

k=2.5 (24^2)

k=1440 so

y=1440/x^2

y (20) = 1440/400=3.6 so y=3.6 when x=20

x^2=1440/y

x^2=1440/16

x^2=90

x=±√90

x=±3√10

approx ...

x=-9.49 and + 9.49 so there are two possible values for x when y=16