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Finding the Fourth Proportional to 879.40, 1,318.62 and 392.20

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Solution

The fourth proportional to 879.40, 1,318.62 and 392.20 is: 588.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    879.40 : 1,318.62 = 392.20 : x
  2. Step 2: Convert to fraction form
    879.40/1,318.62 = 392.20/x
  3. Step 3: Cross multiply
    879.40x = 1,318.62 × 392.20
  4. Step 4: Simplify right side
    879.40x = 517,162.76
  5. Step 5: Solve for x
    x = 517,162.76/879.40
  6. Step 6: Final answer
    x = 588.09

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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.