pro·por·tion·al 
(prə-pôrshə-nəl)
(prə-pôrshə-nəl)adj.
1. Forming a relationship with other parts or quantities; being in proportion.
2. Properly related in size, degree, or other measurable characteristics; corresponding: Punishment ought to be proportional to the crime.
3. Mathematics Having the same or a constant ratio.
n.
One of the quantities in a mathematical proportion.
pro·por′tion·ali·ty (-shə-nălĭ-tē) n.
pro·portion·al·ly adv.