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Finding the Fourth Proportional to 865.92, 1,298.79 and 280.92

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Solution

The fourth proportional to 865.92, 1,298.79 and 280.92 is: 421.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.92 : 1,298.79 = 280.92 : x
  2. Step 2: Convert to fraction form
    865.92/1,298.79 = 280.92/x
  3. Step 3: Cross multiply
    865.92x = 1,298.79 × 280.92
  4. Step 4: Simplify right side
    865.92x = 364,856.09
  5. Step 5: Solve for x
    x = 364,856.09/865.92
  6. Step 6: Final answer
    x = 421.35

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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.