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Finding the Fourth Proportional to 939.72, 1,409.84 and 391.62

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Solution

The fourth proportional to 939.72, 1,409.84 and 391.62 is: 587.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.72 : 1,409.84 = 391.62 : x
  2. Step 2: Convert to fraction form
    939.72/1,409.84 = 391.62/x
  3. Step 3: Cross multiply
    939.72x = 1,409.84 × 391.62
  4. Step 4: Simplify right side
    939.72x = 552,121.54
  5. Step 5: Solve for x
    x = 552,121.54/939.72
  6. Step 6: Final answer
    x = 587.54

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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.