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Finding the Fourth Proportional to 91.72, 127.17 and 86.20

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Solution

The fourth proportional to 91.72, 127.17 and 86.20 is: 119.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.72 : 127.17 = 86.20 : x
  2. Step 2: Convert to fraction form
    91.72/127.17 = 86.20/x
  3. Step 3: Cross multiply
    91.72x = 127.17 × 86.20
  4. Step 4: Simplify right side
    91.72x = 10,961.62
  5. Step 5: Solve for x
    x = 10,961.62/91.72
  6. Step 6: Final answer
    x = 119.51

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.