Let's start with the formula for the area of a triangle
[tex] \frac{1}{2} bh[/tex]
And for the first one, insert the numbers
[tex] \frac{1}{2} 3 \times 6[/tex]
To make this easier, 3×6=18, 1/2 of 18 is 9, so the answer is 9 square feet. There's all you need to complete the rest, good luck .
