1. **State the problem:** Find the points of intersection between the functions $f(x) = \frac{1}{3}x^2$ and $g(x) = -x$, and analyze the right triangle $ABC$ formed by points $A$, $B$, and $C$ where $A$ and $B$ are intersections of the graphs and $C$ lies on the x-axis.
2. **Find intersection points:** Set $f(x) = g(x)$ to find $x$ values where the graphs intersect.
$$\frac{1}{3}x^2 = -x$$
3. **Rewrite the equation:** Multiply both sides by 3 to clear the fraction:
$$3 \times \frac{1}{3}x^2 = 3 \times (-x)$$
$$x^2 = -3x$$
4. **Bring all terms to one side:**
$$x^2 + 3x = 0$$
5. **Factor the quadratic:**
$$x(x + 3) = 0$$
6. **Solve for $x$:**
$$x = 0 \quad \text{or} \quad x = -3$$
7. **Find corresponding $y$ values:**
For $x=0$:
$$y = f(0) = \frac{1}{3} \times 0^2 = 0$$
For $x=-3$:
$$y = f(-3) = \frac{1}{3} \times (-3)^2 = \frac{1}{3} \times 9 = 3$$
8. **Coordinates of intersection points:**
$$A = (-3, 3), \quad B = (0, 0)$$
9. **Point $C$ lies on the x-axis below $A$:**
Since $C$ is on the x-axis, its $y$-coordinate is 0, and it shares the same $x$-coordinate as $A$:
$$C = (-3, 0)$$
10. **Calculate the area of triangle $ABC$:**
Triangle $ABC$ is right-angled at $C$, with legs $AC$ (vertical) and $BC$ (horizontal).
Length of $AC$:
$$|y_A - y_C| = |3 - 0| = 3$$
Length of $BC$:
$$|x_B - x_C| = |0 - (-3)| = 3$$
Area formula for right triangle:
$$\text{Area} = \frac{1}{2} \times AC \times BC = \frac{1}{2} \times 3 \times 3 = \frac{9}{2} = 4.5$$
**Final answer:**
- Intersection points: $A(-3, 3)$ and $B(0, 0)$
- Point $C(-3, 0)$ on x-axis
- Area of triangle $ABC$ is $4.5$ square units.
Intersection Area Cefc1D
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