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Finding the Fourth Proportional to 138.54, 190.89 and 99.66

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Solution

The fourth proportional to 138.54, 190.89 and 99.66 is: 137.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.54 : 190.89 = 99.66 : x
  2. Step 2: Convert to fraction form
    138.54/190.89 = 99.66/x
  3. Step 3: Cross multiply
    138.54x = 190.89 × 99.66
  4. Step 4: Simplify right side
    138.54x = 19,024.10
  5. Step 5: Solve for x
    x = 19,024.10/138.54
  6. Step 6: Final answer
    x = 137.32

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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.