Question

Y is directly proportional to x squared if y=20 when x=2 find y when x= 5

Answer 1

y = 125

Explanation:

Given that,

y is directly proportional to x² i.e.

`y=kx^2`

k is a constant of proportionality

Put y = 20 and x = 2 in the given equation to find k.

`k=(y)/(x^2)\\\\k=(20)/((2)^2)\\\\k=5`

Now put k = 5 and x = 5 in the given equation to find y.

`y=5* (5)^2\\\\y=125`

So, the value of y is equal to 125.