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4-66.

Josie and Jules are building a model car. They find that the real car is 54 inches tall and 180 inches long. They decide to make their model 3 inches tall, but now they are having a disagreement. Josie thinks that their model should be 10 inches long and Jules thinks it should be 129 inches long. Help them settle their argument by deciding if either of them is correct. Explain how you know exactly how long their model should be. Homework Help ✎

Set up a proportion

Substitute in the given information.

Multiply both sides by x to get it in the numerator.

Multiply both sides by 180 to remove the fractions.

Solve for x.

Josie is correct.

$\frac{\text{car height}}{\text{car length}}=\frac{\text{ model height}}{\text{model length}}$

$\frac{54}{180}=\frac{3}{x}$

$x\left(\frac{54}{180}\right)=\left(\frac{3}{x}\right)x$

$\frac{54x}{180}=3$

$180\left(\frac{54x}{180}\right)=3(180)$

54x = 540

x = 10 inches