Step 1: Expression for angular momentum.
\[
L = mvr
\]
Step 2: Orbital speed of earth.
For circular orbit:
\[
v=\sqrt{\frac{GM}{R}}
\]
Step 3: Substituting in angular momentum.
\[
L = mR\sqrt{\frac{GM}{R}} = m\sqrt{GM}\sqrt{R}
\]
Step 4: Conclusion.
Angular momentum is proportional to $\sqrt{R}$.