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Finding the Fourth Proportional to 626.61, 864.66 and 390.90

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Solution

The fourth proportional to 626.61, 864.66 and 390.90 is: 539.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    626.61 : 864.66 = 390.90 : x
  2. Step 2: Convert to fraction form
    626.61/864.66 = 390.90/x
  3. Step 3: Cross multiply
    626.61x = 864.66 × 390.90
  4. Step 4: Simplify right side
    626.61x = 337,995.59
  5. Step 5: Solve for x
    x = 337,995.59/626.61
  6. Step 6: Final answer
    x = 539.40

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.