- Choice G
**45-45-90 triangle ratio**There are two ratios for 45-45-90 triangles:

- The ratio of the sides equals $1:1:\sqrt{2}$
- The ratio of the angles equals 1:1:2

$\therefore OD=\frac{OB}{\sqrt{2}}=\frac{4}{\sqrt{2}}$

- Choice G
**45-45-90 triangle ratio**There are two ratios for 45-45-90 triangles:

- The ratio of the sides equals $1:1:\sqrt{2}$
- The ratio of the angles equals 1:1:2

$\therefore OD=\frac{OB}{\sqrt{2}}=\frac{4}{\sqrt{2}}$