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Finding the Fourth Proportional to 138.50, 208.81 and 131

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Solution

The fourth proportional to 138.50, 208.81 and 131 is: 197.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.50 : 208.81 = 131 : x
  2. Step 2: Convert to fraction form
    138.50/208.81 = 131/x
  3. Step 3: Cross multiply
    138.50x = 208.81 × 131
  4. Step 4: Simplify right side
    138.50x = 27,354.11
  5. Step 5: Solve for x
    x = 27,354.11/138.50
  6. Step 6: Final answer
    x = 197.50

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.