Hi Bobogee
If the permiter is 16 + sq.root(16), the hypotenuse cannot be 16 as specified in the answer.. In fact if the perimeter is 16+sq.root(16), which is 20, and if the hypotenuse is 16, then the remaining 2 sides can have a combined length of 4 ( 20 - 16 ). Since this is a isosceles right triangle, their lengths are to be equal, which means each should of 2 units length. Now lets validate if this correct using the Pythagorus theorem. is (2)^2 + (2)^2 = (16)^2 ? No..
The perimeter must have been 16 + 16*sq.root(2). In this case, you can figure out that the hypotenuse is 16 and the sides are 8*sq.root(2) using the idea that the ratio of the sides of a isosceles right triangle is 1:1:sq.root(2) ( because it is a 45-45-90 triangle )