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Finding the Fourth Proportional to 100.05, 138.09 and 61.23

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Solution

The fourth proportional to 100.05, 138.09 and 61.23 is: 84.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.05 : 138.09 = 61.23 : x
  2. Step 2: Convert to fraction form
    100.05/138.09 = 61.23/x
  3. Step 3: Cross multiply
    100.05x = 138.09 × 61.23
  4. Step 4: Simplify right side
    100.05x = 8,455.25
  5. Step 5: Solve for x
    x = 8,455.25/100.05
  6. Step 6: Final answer
    x = 84.51

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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.