Question

Y is directly proportional to the square of x. When x = 3, y = 4.5. What is y when x is 8?

Answer 1

It’ll be Y=32 it’s easy search

Answer 2

y = 32

Explanation:

Given y is directly proportional to x² then the equation relating them is

y = kx² ← k is the constant of proportion

To find k use the condition when x = 3, y = 4.5 , then

4.5 = k × 3² = 9k ( divide both sides by 9 )

0.5 = k

y = 0.5x² ← equation of proportion

When x = 8 , then

y = 0.5 × 8² = 0.5 × 64 = 32