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Finding the Fourth Proportional to 865.78, 1,299.12 and 379.17

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Solution

The fourth proportional to 865.78, 1,299.12 and 379.17 is: 568.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.78 : 1,299.12 = 379.17 : x
  2. Step 2: Convert to fraction form
    865.78/1,299.12 = 379.17/x
  3. Step 3: Cross multiply
    865.78x = 1,299.12 × 379.17
  4. Step 4: Simplify right side
    865.78x = 492,587.33
  5. Step 5: Solve for x
    x = 492,587.33/865.78
  6. Step 6: Final answer
    x = 568.95

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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.