If this is an isosceles triangle, then it has two 45 degree angles corresponding to two legs of equal length. Â Orient the base of this triangle so that it's horizontal, and represent its length by b. Â Let h represent the height of the triangle. Â Then the area of this right triangle is 50 square inches = (1/2)(b)(h), or A = (b/2)h = 50 in^2. Â Â
Due to the 45 degree angles, the height of this triangle is equal to half the base, or h = b/2. Â Thus, (b/2)h = 50 becomes (b/2)(b/2) = 50, or b^2=200. Thus, b = 10sqrt(2), and h=(1/2)(10 sqrt(2)), or h = 5sqrt(2).
The length of one of the legs is the sqrt of  [5sqrt(2)]^2+[5sqrt(2)]^2, or
sqrt(25(2)+25(2)) = sqrt(100) = 10.