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Finding the Fourth Proportional to 865.40, 1,298.04 and 518.60

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Solution

The fourth proportional to 865.40, 1,298.04 and 518.60 is: 777.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.40 : 1,298.04 = 518.60 : x
  2. Step 2: Convert to fraction form
    865.40/1,298.04 = 518.60/x
  3. Step 3: Cross multiply
    865.40x = 1,298.04 × 518.60
  4. Step 4: Simplify right side
    865.40x = 673,163.54
  5. Step 5: Solve for x
    x = 673,163.54/865.40
  6. Step 6: Final answer
    x = 777.86

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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.