Translation of this question "Se tiene que pegar encaje aun aro de 35 centimetros de diametro¿Cuanto encaje se necesita para cubrirlo? " in English is :
" It has to stick lace even ring of 35 centimeters in diameter How much lace is needed to cover it?"
That means we have to find how much lace is needed to cover ring having diameter of 35 centimeter.
In other words we need to find circumference of the ring.
To maximize area and minimize perimeter we make the dimensions as close to equal as possible. Since we only need fencing on 3 sides, 120/3 = 40; we can use 40 for each side.
