The radius of a circle is increasing at the rate of 1 cm/s. The rate of increase of its area when the radius is 4 cm is:
The radius of a circle is increasing at the rate of 1 cm/s. The rate of increase of its area when the radius is 4 cm is:
- A. 8π cm²/s
- B. 4π cm²/s
- C. 16π cm²/s
- D. 2π cm²/s
Answer: A) 8π cm²/s
Explanation: A = πr². dA/dt = 2πr dr/dt = 2π × 4 × 1 = 8π.
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