If John has a rope that is 15 feet long, how many inches long is the rope?

Step 1 ：First, we know that 1 foot = 12 inches.

Step 2 ：Next, we multiply the length of the rope in feet (15 feet) by the conversion factor of 12 inches/foot.

Step 3 ：\(15 \text{ feet} \times \frac{12 \text{ inches}}{1 \text{ foot}} = 180 \text{ inches}\)