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Finding the Fourth Proportional to 1,392.78, 2,086.34 and 660.14

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Solution

The fourth proportional to 1,392.78, 2,086.34 and 660.14 is: 988.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,392.78 : 2,086.34 = 660.14 : x
  2. Step 2: Convert to fraction form
    1,392.78/2,086.34 = 660.14/x
  3. Step 3: Cross multiply
    1,392.78x = 2,086.34 × 660.14
  4. Step 4: Simplify right side
    1,392.78x = 1,377,276.49
  5. Step 5: Solve for x
    x = 1,377,276.49/1,392.78
  6. Step 6: Final answer
    x = 988.87

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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.