# Chapter 3 - 3.5 - Mathematical Modeling and Variation - 3.5 Exercises - Page 296: 51

$A$ varies jointly as $b$ and $h$.

#### Work Step by Step

It means that if we multiply $b$ by a factor $m$ and $h$ by a factor $n$, then $A$ will be multiplied by a factor $mn$. $A_1=\frac{1}{2}b_1h_1$ Now suppose that $b_2=mb_1$ and $h_2=nh_1$ $A_2=\frac{1}{2}b_2h_2=\frac{1}{2}mb_1nh_1=mn\frac{1}{2}b_1h_1=mnA_1$ $A_2=mnA_1$

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.