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Finding the Fourth Proportional to 100.08, 138.11 and 56.42

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Solution

The fourth proportional to 100.08, 138.11 and 56.42 is: 77.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.08 : 138.11 = 56.42 : x
  2. Step 2: Convert to fraction form
    100.08/138.11 = 56.42/x
  3. Step 3: Cross multiply
    100.08x = 138.11 × 56.42
  4. Step 4: Simplify right side
    100.08x = 7,791.48
  5. Step 5: Solve for x
    x = 7,791.48/100.08
  6. Step 6: Final answer
    x = 77.85

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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.