The proportionality constant "k" is 1.88
<h3><u>Solution:</u></h3>
Given that y varies directly with x
y = 15 when x = 8
To find: proportionality constant "k"
Direct variation means that increase/decrease in one quantity also causes increase/decrease in other quantity.
⇒ y varies directly with x
This means,

Can also be written as:
y = kx
Where "k" is the proportionality constant
Substituting the given values of "x" and "y"
15 = k(8)

k = 1.875
On rounding to nearest hundredths place we get 1.88
Thus the proportionality constant is 1.88