The formula for the area of a triangle, no matter what kind of a triangle it is, is

. We are told that the height is twice the base, so h=2b. We are also told that the area is 49. ∴,

and

and

. If we solve for b we get that b = 7 and -7. Since the only 2 things in math that will never EVER be negative are time and distance/length, -7 is out. Our base is 7 then, and our height is 2(7) which is 14.