To find the area of a triangle, you can use the formula:
\[ \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} \]
From your description, it sounds like the triangle is inscribed in a 10x10 grid, and you mentioned "9 angled squares." However, I need more clarity on what you meant by "9 angled squares."
Assuming that the base of the triangle is 9 units and the height is 6 units (which is a common configuration in a 10x10 grid), the area calculation would be as follows:
\[ \text{Area} = \frac{1}{2} \times 9 \times 6 = \frac{54}{2} = 27 \text{ square units} \]
If the base and height you counted result in a different configuration or a different area, please clarify the base and height measurements or the specific arrangement in the grid. Based on the options you provided, if the base and height were as stated above, the answer would be 27 square units.