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Finding the Fourth Proportional to 866.57, 1,299.87 and 318.80

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Solution

The fourth proportional to 866.57, 1,299.87 and 318.80 is: 478.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    866.57 : 1,299.87 = 318.80 : x
  2. Step 2: Convert to fraction form
    866.57/1,299.87 = 318.80/x
  3. Step 3: Cross multiply
    866.57x = 1,299.87 × 318.80
  4. Step 4: Simplify right side
    866.57x = 414,398.56
  5. Step 5: Solve for x
    x = 414,398.56/866.57
  6. Step 6: Final answer
    x = 478.21

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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.