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Finding the Fourth Proportional to 865.31, 1,297.76 and 280.36

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Solution

The fourth proportional to 865.31, 1,297.76 and 280.36 is: 420.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.31 : 1,297.76 = 280.36 : x
  2. Step 2: Convert to fraction form
    865.31/1,297.76 = 280.36/x
  3. Step 3: Cross multiply
    865.31x = 1,297.76 × 280.36
  4. Step 4: Simplify right side
    865.31x = 363,833.50
  5. Step 5: Solve for x
    x = 363,833.50/865.31
  6. Step 6: Final answer
    x = 420.47

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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.