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Finding the Fourth Proportional to 426.21, 638.70 and 339.15

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Solution

The fourth proportional to 426.21, 638.70 and 339.15 is: 508.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.21 : 638.70 = 339.15 : x
  2. Step 2: Convert to fraction form
    426.21/638.70 = 339.15/x
  3. Step 3: Cross multiply
    426.21x = 638.70 × 339.15
  4. Step 4: Simplify right side
    426.21x = 216,616.38
  5. Step 5: Solve for x
    x = 216,616.38/426.21
  6. Step 6: Final answer
    x = 508.24

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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.