Answer
$A(x)=\dfrac{x^{2}}{2}$, where $x$ is the length of one of the two equal sides
Work Step by Step
The area $A$ of a triangle is given by the formula $A=\dfrac{bh}{2}$ where $b$ is the base and $h$ is the height.
In an isosceles right triangle, the base and the height are equal, hence, if we let $x$ be one of the two equal sides, then
$A=\dfrac{x \cdot x}{2}$
$A=\dfrac{x^{2}}{2}$
Thus, expressing the area of an isosceles right triangle as a function of one of the two equal sides yields:
$A(x)=\dfrac{x^2}{2}$. where $x$ is the length of one of the two equal sides.
