## Basic College Mathematics (9th Edition)

$x=12$ mm $y=7.5$ mm Perimeter: 38 mm
To solve for side $x$, we set up a proportion with corresponding sides: $\displaystyle \frac{16}{12}=\frac{x}{9}$ Cross-multiply: $16*9=12x$ $12x=144$ $x=144/12$ $x=12$ mm Similarly, we set up another proportion to solve for $y$: $\displaystyle \frac{16}{12}=\frac{10}{y}$ Cross-multiply: $16y=10*12$ $16y=120$ $y=120/16$ $y=7.5$ mm Finally, we find the perimeter of the large triangle: $12+10+16=38$ mm