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Finding the Fourth Proportional to 939.89, 1,407.39 and 648.29

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Solution

The fourth proportional to 939.89, 1,407.39 and 648.29 is: 970.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.89 : 1,407.39 = 648.29 : x
  2. Step 2: Convert to fraction form
    939.89/1,407.39 = 648.29/x
  3. Step 3: Cross multiply
    939.89x = 1,407.39 × 648.29
  4. Step 4: Simplify right side
    939.89x = 912,389.83
  5. Step 5: Solve for x
    x = 912,389.83/939.89
  6. Step 6: Final answer
    x = 970.75

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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.