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Finding the Fourth Proportional to 865.98, 1,299.56 and 318.60

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Solution

The fourth proportional to 865.98, 1,299.56 and 318.60 is: 478.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.98 : 1,299.56 = 318.60 : x
  2. Step 2: Convert to fraction form
    865.98/1,299.56 = 318.60/x
  3. Step 3: Cross multiply
    865.98x = 1,299.56 × 318.60
  4. Step 4: Simplify right side
    865.98x = 414,038.22
  5. Step 5: Solve for x
    x = 414,038.22/865.98
  6. Step 6: Final answer
    x = 478.12

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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.