Question 510361
diagonal cuts rectangle into two triangles. Solve either triangle.

119 = leg = a
169 = hypotenuse = c

Find b.

a^2 + b^2 = c^2

119^2 + b^2 = 169^2

14161 + b^2 = 28561

b^2 = 14400

b = 120

So the length is 120.