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Finding the Fourth Proportional to 103.62, 142.90 and 80.31

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Solution

The fourth proportional to 103.62, 142.90 and 80.31 is: 110.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.62 : 142.90 = 80.31 : x
  2. Step 2: Convert to fraction form
    103.62/142.90 = 80.31/x
  3. Step 3: Cross multiply
    103.62x = 142.90 × 80.31
  4. Step 4: Simplify right side
    103.62x = 11,476.30
  5. Step 5: Solve for x
    x = 11,476.30/103.62
  6. Step 6: Final answer
    x = 110.75

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.