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Finding the Fourth Proportional to 659.38, 989.22 and 220.78

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Solution

The fourth proportional to 659.38, 989.22 and 220.78 is: 331.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    659.38 : 989.22 = 220.78 : x
  2. Step 2: Convert to fraction form
    659.38/989.22 = 220.78/x
  3. Step 3: Cross multiply
    659.38x = 989.22 × 220.78
  4. Step 4: Simplify right side
    659.38x = 218,399.99
  5. Step 5: Solve for x
    x = 218,399.99/659.38
  6. Step 6: Final answer
    x = 331.22

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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.