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Finding the Fourth Proportional to 1,425.60, 2,138.40 and 871.20

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Solution

The fourth proportional to 1,425.60, 2,138.40 and 871.20 is: 1,306.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,425.60 : 2,138.40 = 871.20 : x
  2. Step 2: Convert to fraction form
    1,425.60/2,138.40 = 871.20/x
  3. Step 3: Cross multiply
    1,425.60x = 2,138.40 × 871.20
  4. Step 4: Simplify right side
    1,425.60x = 1,862,974.08
  5. Step 5: Solve for x
    x = 1,862,974.08/1,425.60
  6. Step 6: Final answer
    x = 1,306.80

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.