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Finding the Fourth Proportional to 138.45, 191.11 and 86.00

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Solution

The fourth proportional to 138.45, 191.11 and 86.00 is: 118.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.45 : 191.11 = 86.00 : x
  2. Step 2: Convert to fraction form
    138.45/191.11 = 86.00/x
  3. Step 3: Cross multiply
    138.45x = 191.11 × 86.00
  4. Step 4: Simplify right side
    138.45x = 16,435.53
  5. Step 5: Solve for x
    x = 16,435.53/138.45
  6. Step 6: Final answer
    x = 118.71

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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.