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Finding the Fourth Proportional to 939.40, 1,409.60 and 391.96

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Solution

The fourth proportional to 939.40, 1,409.60 and 391.96 is: 588.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    939.40 : 1,409.60 = 391.96 : x
  2. Step 2: Convert to fraction form
    939.40/1,409.60 = 391.96/x
  3. Step 3: Cross multiply
    939.40x = 1,409.60 × 391.96
  4. Step 4: Simplify right side
    939.40x = 552,501.63
  5. Step 5: Solve for x
    x = 552,501.63/939.40
  6. Step 6: Final answer
    x = 588.14

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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.