Michelle,

If you have an equilateral triangle with each side of length s units then you can find the height, h, of the triangle using the expression

The instruction "Solve for s" is asking you to manipulate this equation to arrive at the form

s = some expression involving h.

To do this I would first take the original expression and multiple both sides by 2 to obtain

2h = √3 s.

Now divide both sides by √3 and the expression becomes

(2h)/√3 = s,

or written more neatly

I hope this helps,
Penny