Chapter 8 - Right Triangles and Trigonometry - 8-2 Special Right Triangles - Practice and Problem-Solving Exercises - Page 505: 40

$x = \frac{12}{7}$

We solve a proportion by first eliminating fractions. We use the cross products property where we multiply the numerator of one fraction with the denominator of the other, and vice versa: $7x = 12$ Divide each side by $7$ to solve for $x$: $x = \frac{12}{7}$