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Finding the Fourth Proportional to 100.11, 138.09 and 84.66

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Solution

The fourth proportional to 100.11, 138.09 and 84.66 is: 116.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.11 : 138.09 = 84.66 : x
  2. Step 2: Convert to fraction form
    100.11/138.09 = 84.66/x
  3. Step 3: Cross multiply
    100.11x = 138.09 × 84.66
  4. Step 4: Simplify right side
    100.11x = 11,690.70
  5. Step 5: Solve for x
    x = 11,690.70/100.11
  6. Step 6: Final answer
    x = 116.78

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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.