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Finding the Fourth Proportional to 866.80, 1,299.36 and 318.64

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Solution

The fourth proportional to 866.80, 1,299.36 and 318.64 is: 477.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    866.80 : 1,299.36 = 318.64 : x
  2. Step 2: Convert to fraction form
    866.80/1,299.36 = 318.64/x
  3. Step 3: Cross multiply
    866.80x = 1,299.36 × 318.64
  4. Step 4: Simplify right side
    866.80x = 414,028.07
  5. Step 5: Solve for x
    x = 414,028.07/866.80
  6. Step 6: Final answer
    x = 477.65

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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.