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Finding the Fourth Proportional to 866.80, 1,299.42 and 318.60

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Solution

The fourth proportional to 866.80, 1,299.42 and 318.60 is: 477.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    866.80 : 1,299.42 = 318.60 : x
  2. Step 2: Convert to fraction form
    866.80/1,299.42 = 318.60/x
  3. Step 3: Cross multiply
    866.80x = 1,299.42 × 318.60
  4. Step 4: Simplify right side
    866.80x = 413,995.21
  5. Step 5: Solve for x
    x = 413,995.21/866.80
  6. Step 6: Final answer
    x = 477.61

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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.