SAT Prep | Mastering Ratios and Proportions: Overview

The ratio of two numbers x and y written x : y is the fraction where . A ratio compares x to y by dividing one by the other. Therefore, in order to compare ratios, simply compare the fractions.

A proportion is an equality of two ratios. The laws of proportion are listed below.

If , then

(A) ad bd

(B)

(C)

(D)

(E)

Given a proportion a : b = c : d, then a and d are called extremes, b and c are called the means, and d is called the fourth proportion to a, b, and c.

PROBLEMSolve the proportion.

SOLUTION
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