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Finding the Fourth Proportional to 748.78, 1,123.28 and 261.72

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Solution

The fourth proportional to 748.78, 1,123.28 and 261.72 is: 392.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    748.78 : 1,123.28 = 261.72 : x
  2. Step 2: Convert to fraction form
    748.78/1,123.28 = 261.72/x
  3. Step 3: Cross multiply
    748.78x = 1,123.28 × 261.72
  4. Step 4: Simplify right side
    748.78x = 293,984.84
  5. Step 5: Solve for x
    x = 293,984.84/748.78
  6. Step 6: Final answer
    x = 392.62

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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.