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Let the median of a variable equilateral triangle is increasing at the rate of 232\sqrt{3} cm/s. Then the rate at which its each side is increasing is:

Solution

✅ Correct Option: 4

For an equilateral triangle of side aa, the median equals the altitude: m=32am=\frac{\sqrt3}{2}a.

Differentiating, dmdt=32dadt\frac{dm}{dt}=\frac{\sqrt3}{2}\frac{da}{dt}.

So 23=32dadt2\sqrt3=\frac{\sqrt3}{2}\frac{da}{dt}, giving dadt=4\frac{da}{dt}=4 cm/s.

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