We can use a proportion to solve problems that involve scale factors. Every 25 feet equals 10 inches, according to Ella's scale model. The building is actually 450 feet tall, so feet and inches are our units for the proportion. The first step is to set up the proportion:
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Notice the feet (450 and 25) are lined up next to each other, and the inches (x and 10) are lined up as well. Next, we solve by cross multiplying and dividing. 450 times 10 gives us 4500. Then, we divide by the remaining number,25. 4500/25 equals 180. So, Ella's model is 180 inches tall.
Notice the feet (450 and 25) are lined up next to each other, and the inches (x and 10) are lined up as well. Next, we solve by cross multiplying and dividing. 450 times 10 gives us 4500. Then, we divide by the remaining number,25. 4500/25 equals 180. So, Ella's model is 180 inches tall.