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Finding the Fourth Proportional to 100.09, 138.11 and 56.43

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Solution

The fourth proportional to 100.09, 138.11 and 56.43 is: 77.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.09 : 138.11 = 56.43 : x
  2. Step 2: Convert to fraction form
    100.09/138.11 = 56.43/x
  3. Step 3: Cross multiply
    100.09x = 138.11 × 56.43
  4. Step 4: Simplify right side
    100.09x = 7,793.55
  5. Step 5: Solve for x
    x = 7,793.55/100.09
  6. Step 6: Final answer
    x = 77.87

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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.