Hello,
Let's put what we know in an equation. We know that B X H / 2 = the area of a triangle.
6 X H (height) / 2 = 10.5 Sq. Ft.
If you want to find the height, let's solve for H. I think we should combine 6 and H together, and that would simplify to 6h / 2 = 10.5.
Now to get 6h by itself, let's multiply by 2 to each side. It would then look like: 6h = 21. To finally get "h" by itself, we need to divide h by 6 to each sides. After you do that, the answer simplified is: h = 3.5.
To make sure my answer is correct, let's plug in the height with the base, if it equals 10.5.
6 X 3.5 / 2 = 10.5
(6 X 3.5 ) / 2 = 10.5
(21) / 2 = 10.5
10.5 = 10.5
My answer is correct, since each side equals the same. Hope this isn't too confusing, hope this helps! =)