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Finding the Fourth Proportional to 866.60, 1,299.98 and 318.78

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Solution

The fourth proportional to 866.60, 1,299.98 and 318.78 is: 478.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    866.60 : 1,299.98 = 318.78 : x
  2. Step 2: Convert to fraction form
    866.60/1,299.98 = 318.78/x
  3. Step 3: Cross multiply
    866.60x = 1,299.98 × 318.78
  4. Step 4: Simplify right side
    866.60x = 414,406.03
  5. Step 5: Solve for x
    x = 414,406.03/866.60
  6. Step 6: Final answer
    x = 478.20

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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.