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If y is directly proportional to x², and when x = 2, y = 20, what is the value of y when x = 3?

If y is directly proportional to x², and when x = 2, y = 20, what is the value of y when x = 3?

Explanation
  • Since y ∝ x², we use the formula y = kx².

  • Given y = 20 when x = 2, we find k = 5, so when x = 3, y = 5(3²) = 45.