Question

The diagonal of a square is changing at the rate of $0.5$ cm/sec. Then the rate of change of area when the area is $400$ cm$^{2}$ is equal to}

• A. $20\sqrt{2}$ cm$^{2}$/sec
• B. $10\sqrt{2}$ cm$^{2}$/sec
• C. $\frac{1}{10\sqrt{2$ cm$^{2}$/sec
• D. $\frac{10}{\sqrt{2$ cm$^{2}$/sec

Hint:

For related rates problems, first identify all variables and their relationships (e.g., geometric formulas). Differentiate the primary equation with respect to time. Then, substitute known rates and specific values to find the unknown rate. Always pay attention to units.

Answer 1

The Correct Option is C