Both triangles are right triangles. x is the hypotenuse of the upper one. ThePythagorean formula will give the value of x. One side is known, The other side we will find using the fact that the lower right triangle is isosceles. The hypotenuse of an isosceles right triangle has a length of 
times the length of one of the legs. In this case 14. So the hypotenuse of the lower triangle is also the short side of the upper triangle. Using Pythagoras
