The problem is to evaluate the expression $\sqrt{100 \times 121} = \sqrt{100 \times \sqrt{21}}$. It seems there is a typo in the right-hand side expression. Let's evaluate the left-hand side expression $\sqrt{100 \times 121}$.

1. Problem Description

The problem is to evaluate the expression $\sqrt{100 \times 121} = \sqrt{100 \times \sqrt{21}}$. It seems there is a typo in the right-hand side expression. Let's evaluate the left-hand side expression $\sqrt{100 \times 121}$.

2. Solution Steps

We are asked to evaluate $\sqrt{100 \times 121}$.

We know that $\sqrt{a \times b} = \sqrt{a} \times \sqrt{b}$.

Therefore, $\sqrt{100 \times 121} = \sqrt{100} \times \sqrt{121}$.

We know that $\sqrt{100} = 10$ and $\sqrt{121} = 11$.

Therefore, $\sqrt{100 \times 121} = 10 \times 11 = 110$.

3. Final Answer

The final answer is 110.