Hi there, I am asked this scenario:

The sides of an equilateral triangle are decreasing at a rate of da/dt=-(root6) cm. Find the rate of change of:

a) The area of the triangle

b) The height

I have drawn a diagram but I don't know how to go on about solving these problems

So i Know that for a) I'm meant to find da/dt

b) dh/dt

But I don't know to do arrive at the answer...please help.