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Finding the Fourth Proportional to 638.72, 959.70 and 407.72

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Solution

The fourth proportional to 638.72, 959.70 and 407.72 is: 612.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.72 : 959.70 = 407.72 : x
  2. Step 2: Convert to fraction form
    638.72/959.70 = 407.72/x
  3. Step 3: Cross multiply
    638.72x = 959.70 × 407.72
  4. Step 4: Simplify right side
    638.72x = 391,288.88
  5. Step 5: Solve for x
    x = 391,288.88/638.72
  6. Step 6: Final answer
    x = 612.61

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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.