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Finding the Fourth Proportional to 865.69, 1,298.21 and 280.66

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Solution

The fourth proportional to 865.69, 1,298.21 and 280.66 is: 420.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.69 : 1,298.21 = 280.66 : x
  2. Step 2: Convert to fraction form
    865.69/1,298.21 = 280.66/x
  3. Step 3: Cross multiply
    865.69x = 1,298.21 × 280.66
  4. Step 4: Simplify right side
    865.69x = 364,355.62
  5. Step 5: Solve for x
    x = 364,355.62/865.69
  6. Step 6: Final answer
    x = 420.88

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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.