Answer:
y = 75
Step-by-step explanation:
Given that:
y [tex]\alpha[/tex] [tex]\sqrt{x}[/tex]
⇒ y = k[tex]\sqrt{x}[/tex]
where k is the constant of proportionality.
When y = 45, x = 81, then;
45 = k[tex]\sqrt{81}[/tex]
45 = 9 k
k = [tex]\frac{45}{9}[/tex]
= 5
k = 5
So that,
y = 5[tex]\sqrt{x}[/tex]
the value of y when x = 225 is;
y = 5[tex]\sqrt{x}[/tex]
= 5 x [tex]\sqrt{225}[/tex]
= 5 x 15
y = 75
