Answer
C. 50
Work Step by Step
We are given that the length and width of a rectangle are $\sqrt 26$ and $\sqrt 98$.
Since 26 is close to 25, we can use the fact that $\sqrt 25=5$ to approximate $\sqrt 26$ as 5.
Since 98 is close to 100, we can use the fact that $\sqrt 100=10$ to approximate $\sqrt 98$ as 10.
Furthermore, we know that the formula for the area of a rectangle is $l\times w$. Using our approximations, $l\times w=5\times10=50$.