What is the formula for the width of a rectangle?
The area ,A, of a rectangle is the length, L, multiplied by the
width, W. A=LW hence W=A/L. The perimeter, P, of a rectangle is P=
2(L+W) or 2L+2W. 2W=P-2L and W=(P/2)-L. The Square of the diagonal
of a rectangle, D^2 =W^2+L^2 so that W^2=D^2-L^2 and
W=sqrt((D^2-L^2). You could also express the width using
trigonometric functions, but this is probably enough to get you
started.