Question

the side of an equilateral triangle is increasing at the rate of 0.5 cm+sec .find the rate of increase of its perimeter

Answer 1

As a triangle has 3 sides, its perimeter will increase at thrice the rate of increase of a side.

hence: the rate of increase of perimeter = 1.5cm/sec

Hope this helps :)

Answer 2

da/dt=0.5

perimeter=p=3a

dp/dt=3da/dt=1.5cm/s