Final answer:
To write the ratio 12:9 as an equivalent fraction of 4:x, set up a proportion and cross multiply to solve for x.
Step-by-step explanation:
To write the ratio 12:9 as an equivalent fraction of 4:x, you need to set up a proportion. Start by writing the ratio as a fraction, 12/9. Then, set up the proportion: 12/9 = 4/x. Next, cross multiply to solve for x: 12x = 4 * 9. Finally, divide both sides of the equation by 12 to solve for x: x = (4 * 9) / 12. The equivalent fraction of 12:9 as 4:x is (4 * 9) / 12.