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Finding the Fourth Proportional to 100.86, 138.94 and 76.29

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Solution

The fourth proportional to 100.86, 138.94 and 76.29 is: 105.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.86 : 138.94 = 76.29 : x
  2. Step 2: Convert to fraction form
    100.86/138.94 = 76.29/x
  3. Step 3: Cross multiply
    100.86x = 138.94 × 76.29
  4. Step 4: Simplify right side
    100.86x = 10,599.73
  5. Step 5: Solve for x
    x = 10,599.73/100.86
  6. Step 6: Final answer
    x = 105.09

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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.