To find the area of a triangle, you can use the formula:
\[ \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} \]
Since you mentioned that the base of the triangle is 3 full squares, we can assume that the base length is 3 units.
Next, we'll need to determine the height of the triangle. If you counted the height by squares, please provide the height value. If you say that the height is, for example, 8 square units, then you would plug that value into the formula.
Let's assume the height is also known; for demonstration purposes, let's say the height is 8 square units.
Using the values:
\[ \text{Area} = \frac{1}{2} \times 3 \times 8 = \frac{24}{2} = 12 \text{ square units} \]
However, if the height is different, you would need to adjust the calculation accordingly. Please specify the height if you want an exact answer!