To determine the area of a triangle, you can use the formula:
[tex]\[ \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} \][/tex]
Given the base is 3 feet and the height is 6 feet, we can substitute these values into the formula:
[tex]\[ \text{Area} = \frac{1}{2} \times 3 \text{ feet} \times 6 \text{ feet} \][/tex]
First, multiply the base and the height:
[tex]\[ 3 \text{ feet} \times 6 \text{ feet} = 18 \text{ square feet} \][/tex]
Next, multiply by [tex]\(\frac{1}{2}\)[/tex]:
[tex]\[ \frac{1}{2} \times 18 \text{ square feet} = 9 \text{ square feet} \][/tex]
The area of the triangle is [tex]\(9 \text{ ft}^2\)[/tex].
So, the correct answer is:
[tex]\[ \boxed{9 \text{ ft}^2} \][/tex]