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Finding the Fourth Proportional to 415.78, 623.72 and 138.10

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Solution

The fourth proportional to 415.78, 623.72 and 138.10 is: 207.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    415.78 : 623.72 = 138.10 : x
  2. Step 2: Convert to fraction form
    415.78/623.72 = 138.10/x
  3. Step 3: Cross multiply
    415.78x = 623.72 × 138.10
  4. Step 4: Simplify right side
    415.78x = 86,135.73
  5. Step 5: Solve for x
    x = 86,135.73/415.78
  6. Step 6: Final answer
    x = 207.17

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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.