$$\dfrac{2100 lbf}{15 lbf/ft}$$ $$\dfrac{2100 lbf}{15\dfrac{lbf}{ft^2}}$$ $$S = \dfrac{2100 lbf}{15\dfrac{lbf}{ft^2}}$$ $$S = 140 ft^2$$

You are quite welcome. Majored in Math; heard of LaTex and Knuth as undergrad. Percy in Sopchoppy, FL

I haven't used LaTex for a number of years. It seems to be mainly used to self type-set papers for various technical journals. It makes beautiful reports but is not user friendly. I have downloaded "TeXstudio" to help me with the correct syntax. Frankly, I was surprised to see it here.