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Finding the Fourth Proportional to 138.20, 190.77 and 99.45

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Solution

The fourth proportional to 138.20, 190.77 and 99.45 is: 137.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.20 : 190.77 = 99.45 : x
  2. Step 2: Convert to fraction form
    138.20/190.77 = 99.45/x
  3. Step 3: Cross multiply
    138.20x = 190.77 × 99.45
  4. Step 4: Simplify right side
    138.20x = 18,972.08
  5. Step 5: Solve for x
    x = 18,972.08/138.20
  6. Step 6: Final answer
    x = 137.28

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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.