Question

y is directly proportional to the square of x. When x = 3, y = 36.Find the value of y when x = 5

Answer 1

help

Answer 2

If y is directly proportional to the square of x, there is some number you multiply x² by to get x:
y=kx²
This constant, k, will be the same for any value of x.
Can you find k if you know that y=36 when x=3?
Hint: Use the known values for x and y in the formula y=kx²

Answer 3

y=kx²
36=k3²
36=9k
k=36/9
k=4k

y=4²k???

Answer 4

is that right so far

Answer 5

y is directly proportional to the square of x. When x = 3, y = 36.Find the value of y when x = 5


help

Answer 6

help please

Answer 7

So, you found that k=4. Well done!
Now, just plug that into the equation, but with x=5:
y=kx²
y=4(5²)
y=4(25)
y=100

Answer 8

thank you..that is where I was getting confused

Answer 9

hw do you give someone a medal

Answer 10

A, B, C and D are points on the circumference of a circle, centre O.
Angle AOC = y.
Find the size of angle ABC in terms of y.
Give a reason for each stage of your working.