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Finding the Fourth Proportional to 138.66, 208.17 and 84.66

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Solution

The fourth proportional to 138.66, 208.17 and 84.66 is: 127.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.66 : 208.17 = 84.66 : x
  2. Step 2: Convert to fraction form
    138.66/208.17 = 84.66/x
  3. Step 3: Cross multiply
    138.66x = 208.17 × 84.66
  4. Step 4: Simplify right side
    138.66x = 17,623.67
  5. Step 5: Solve for x
    x = 17,623.67/138.66
  6. Step 6: Final answer
    x = 127.10

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.