So we can use the formula 2lw +2wh+ 2lh, which is the surface area formula and we can set that to equal 20. 2lw +2wh+ 2lh=20
lw+wh+lh= 10
Let’s isolate L
Lw+Lh=10-wh
Let’s distribute L
L(w+h)=10-wh
L=(10-wh)/(w+h)
You can use this formula to plug in values for w and h and it will work as long as their products are less than 10
