1. The problem states that $y$ is proportional to $x^2$, which means we can write the relation as: $$y = kx^2$$ where $k$ is the constant of proportionality. 2. We are given that when $x=2$, $y=20$. Substitute these values into the equation to find $k$: $$20 = k \times 2^2$$ $$20 = k \times 4$$ 3. Solve for $k$: $$k = \frac{20}{4}$$ $$k = 5$$ 4. Now we have the relation between $x$ and $y$: $$y = 5x^2$$ 5. To find the value of $y$ when $x=1\frac{a}{b}3$, interpret $1\frac{a}{b}3$ as $1 + \frac{a}{b} + 3 = 4 + \frac{a}{b}$ (assuming the user means a mixed number plus 3). Since $a$ and $b$ are not specified, we keep it symbolic: $$x = 4 + \frac{a}{b}$$ 6. Substitute $x$ into the relation: $$y = 5 \left(4 + \frac{a}{b}\right)^2$$ This is the value of $y$ in terms of $a$ and $b$ when $x=1\frac{a}{b}3$. Final answers: - Relation: $y = 5x^2$ - Value of $y$ at $x=4 + \frac{a}{b}$ is $y = 5 \left(4 + \frac{a}{b}\right)^2$