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Finding the Fourth Proportional to 939.29, 1,409.07 and 391.50

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Solution

The fourth proportional to 939.29, 1,409.07 and 391.50 is: 587.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.29 : 1,409.07 = 391.50 : x
  2. Step 2: Convert to fraction form
    939.29/1,409.07 = 391.50/x
  3. Step 3: Cross multiply
    939.29x = 1,409.07 × 391.50
  4. Step 4: Simplify right side
    939.29x = 551,650.91
  5. Step 5: Solve for x
    x = 551,650.91/939.29
  6. Step 6: Final answer
    x = 587.31

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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.