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Finding the Fourth Proportional to 748.78, 1,123.20 and 286.60

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Solution

The fourth proportional to 748.78, 1,123.20 and 286.60 is: 429.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    748.78 : 1,123.20 = 286.60 : x
  2. Step 2: Convert to fraction form
    748.78/1,123.20 = 286.60/x
  3. Step 3: Cross multiply
    748.78x = 1,123.20 × 286.60
  4. Step 4: Simplify right side
    748.78x = 321,909.12
  5. Step 5: Solve for x
    x = 321,909.12/748.78
  6. Step 6: Final answer
    x = 429.91

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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.