Question 16A circle of radius $r$ is inscribed in a right isosceles triangle, and a circle of radius $R$ is circumscribed about the triangle. Then $\frac{R}{r}$ equals$1+\sqrt2$$\frac{2+\sqrt2}{2}$$\frac{\sqrt2-1}{2}$$\frac{1+\sqrt2}{2}$$2(2-\sqrt2)$