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Finding the Fourth Proportional to 1,381.11, 2,072.70 and 861.87

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Solution

The fourth proportional to 1,381.11, 2,072.70 and 861.87 is: 1,293.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,381.11 : 2,072.70 = 861.87 : x
  2. Step 2: Convert to fraction form
    1,381.11/2,072.70 = 861.87/x
  3. Step 3: Cross multiply
    1,381.11x = 2,072.70 × 861.87
  4. Step 4: Simplify right side
    1,381.11x = 1,786,397.95
  5. Step 5: Solve for x
    x = 1,786,397.95/1,381.11
  6. Step 6: Final answer
    x = 1,293.45

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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.