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Finding the Fourth Proportional to 939.31, 1,409.06 and 391.19

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Solution

The fourth proportional to 939.31, 1,409.06 and 391.19 is: 586.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.31 : 1,409.06 = 391.19 : x
  2. Step 2: Convert to fraction form
    939.31/1,409.06 = 391.19/x
  3. Step 3: Cross multiply
    939.31x = 1,409.06 × 391.19
  4. Step 4: Simplify right side
    939.31x = 551,204.11
  5. Step 5: Solve for x
    x = 551,204.11/939.31
  6. Step 6: Final answer
    x = 586.82

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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.