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Finding the Fourth Proportional to 865.20, 1,288.62 and 861.02

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Solution

The fourth proportional to 865.20, 1,288.62 and 861.02 is: 1,282.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.20 : 1,288.62 = 861.02 : x
  2. Step 2: Convert to fraction form
    865.20/1,288.62 = 861.02/x
  3. Step 3: Cross multiply
    865.20x = 1,288.62 × 861.02
  4. Step 4: Simplify right side
    865.20x = 1,109,521.15
  5. Step 5: Solve for x
    x = 1,109,521.15/865.20
  6. Step 6: Final answer
    x = 1,282.39

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.