Unequal masses will not balance on a fulcrum if they are at an equal distance from it; one side will go up and the other side will go down. Unequal masses will balance when the following proportion is true:

$\frac{\mathrm{mass} 1}{ \mathrm{length} 2}=\frac{\mathrm{mass} 2}{\mathrm{length} 1}$

Two children can be balanced on a seesaw when $\frac{\mathrm{mass} 1}{ \mathrm{length} 2}=\frac{\mathrm{mass} 2}{\mathrm{length} 1}$. The child on the left and the child on the right are balanced. If the mass of the child on the right is $p \mathrm{kg}$, find $p$.