Mark the correct alternative in the following:
Side of an equilateral triangle expands at the rate of 2 cm/sec. The rate of increase of its area when each side is 10 cm is
The area of an equilateral triangle, with side a, is defined as
– (1)
Given that 
and a=10cm, we have to calculate 
Differentiating (1) with respect to t, we get
Substituting the values, we get
=10√3 cm2 /sec
1