hihi. So you can use the Pythagorean theorem to find any missing sides to a triangle. The equation goes like this: a^2 + b^2 = c^2, where a a and b are the lengths of the 2 bases of the triangle and c is the length of the hypothenuse/longest side to the triangle. Since you know the length of the hypothenuse and of one of the bases you can solve for the last base using the equation which gets you ~8.246. Now, adding that to the other side lengths gets you 28.246 as an approximate perimeter to 3 sig figs
