SOLUTION: y varies directly as the square of x. If y=80 when x=20. Find y when x=90

SOLUTION: y varies directly as the square of x. If y=80 when x=20. Find y when x=90

Algebra.Com

Question 760510: y varies directly as the square of x. If y=80 when x=20. Find y when x=90
Answer by ramkikk66(644) (Show Source): You can put this solution on YOUR website!
y varies directly as the square of x. This means that the ratio of y to x^2 is a constant. Let us call it k. Mathematically,

y = 80 when x = 20. Substituting for y and x in the above equation,
or

So when x = 90,

Therefore, or

RELATED QUESTIONS
if y varies directly as the square of x, and y = 32, when x = 2, find y when x =... (answered by bucky)

If y varies directly as the square of x, and y=7 when x=9, find y when... (answered by midwood_trail)

Y varies directly as x and inversley as the square of 2,y=25 when X=80 and Z =4 find Y... (answered by vleith)

Y varies directly as x and inversely as the square of z. y=10 when x=80 and z =4. Find y... (answered by stanbon)

y varies directly as x and inversely as the square of z. y= 14 when x=50 and z=5. Find... (answered by josgarithmetic)

Y varies directly as the square root of X, and Y=8 when X=9. Find Y when... (answered by Mathtut)

y varies directly as the square of x. When x = 2, y = 40. Find x when y =... (answered by solver91311)

Y varies directly X and inversely as the square of z. Y=50 when x=90 and z=3. Find y... (answered by solver91311)

If y varies as directly as the square of x , and y =75/8 when x =5 ,find y when x... (answered by Theo,MathTherapy,josgarithmetic)