Description: Sal uses the Pythagorean theorem to find area of an isosceles triangle. Recognize, this is an isosceles triangle, and another hint is that the Pythagorean Theorem might be useful. So, we might all remember that the area of a triangle is equal to one half times our base times our height. So, if we can figure that out, then we can calculate what one half times the base 10 times the height is.*Teacher Advisor is 100% free.