Question: Find the area of the triangle pictured above.
Graph: an isosceles triangle with base 9 at the bottom and a dashed vertical height 9 from the top vertex to the midpoint of the base; position_hint=top-left
1. **State the problem:** We need to find the area of an isosceles triangle with a base of $9$ units and a height of $9$ units.
2. **Formula for the area of a triangle:** The area $A$ of a triangle is given by the formula:
$$A = \frac{1}{2} \times \text{base} \times \text{height}$$
3. **Substitute the given values:** Here, the base $b = 9$ and the height $h = 9$. So,
$$A = \frac{1}{2} \times 9 \times 9$$
4. **Calculate the area:**
$$A = \frac{1}{2} \times 81 = \frac{81}{2}$$
5. **Simplify the fraction:**
$$A = 40.5$$
6. **Conclusion:** The area of the triangle is $40.5$ square units.