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Finding the Fourth Proportional to 865.38, 1,297.90 and 280.45

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Solution

The fourth proportional to 865.38, 1,297.90 and 280.45 is: 420.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.38 : 1,297.90 = 280.45 : x
  2. Step 2: Convert to fraction form
    865.38/1,297.90 = 280.45/x
  3. Step 3: Cross multiply
    865.38x = 1,297.90 × 280.45
  4. Step 4: Simplify right side
    865.38x = 363,996.06
  5. Step 5: Solve for x
    x = 363,996.06/865.38
  6. Step 6: Final answer
    x = 420.62

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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.