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Finding the Fourth Proportional to 1,380.92, 2,072.38 and 861.68

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Solution

The fourth proportional to 1,380.92, 2,072.38 and 861.68 is: 1,293.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,380.92 : 2,072.38 = 861.68 : x
  2. Step 2: Convert to fraction form
    1,380.92/2,072.38 = 861.68/x
  3. Step 3: Cross multiply
    1,380.92x = 2,072.38 × 861.68
  4. Step 4: Simplify right side
    1,380.92x = 1,785,728.40
  5. Step 5: Solve for x
    x = 1,785,728.40/1,380.92
  6. Step 6: Final answer
    x = 1,293.14

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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.