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Finding the Fourth Proportional to 103.91, 143.28 and 100.71

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Solution

The fourth proportional to 103.91, 143.28 and 100.71 is: 138.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.91 : 143.28 = 100.71 : x
  2. Step 2: Convert to fraction form
    103.91/143.28 = 100.71/x
  3. Step 3: Cross multiply
    103.91x = 143.28 × 100.71
  4. Step 4: Simplify right side
    103.91x = 14,429.73
  5. Step 5: Solve for x
    x = 14,429.73/103.91
  6. Step 6: Final answer
    x = 138.87

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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.