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Finding the Fourth Proportional to 103.17, 142.11 and 99.21

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Solution

The fourth proportional to 103.17, 142.11 and 99.21 is: 136.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.17 : 142.11 = 99.21 : x
  2. Step 2: Convert to fraction form
    103.17/142.11 = 99.21/x
  3. Step 3: Cross multiply
    103.17x = 142.11 × 99.21
  4. Step 4: Simplify right side
    103.17x = 14,098.73
  5. Step 5: Solve for x
    x = 14,098.73/103.17
  6. Step 6: Final answer
    x = 136.66

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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.