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Finding the Fourth Proportional to 426.63, 639.92 and 138.07

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Solution

The fourth proportional to 426.63, 639.92 and 138.07 is: 207.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.63 : 639.92 = 138.07 : x
  2. Step 2: Convert to fraction form
    426.63/639.92 = 138.07/x
  3. Step 3: Cross multiply
    426.63x = 639.92 × 138.07
  4. Step 4: Simplify right side
    426.63x = 88,354.12
  5. Step 5: Solve for x
    x = 88,354.12/426.63
  6. Step 6: Final answer
    x = 207.10

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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.