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Finding the Fourth Proportional to 127.31, 190.58 and 81.71

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Solution

The fourth proportional to 127.31, 190.58 and 81.71 is: 122.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    127.31 : 190.58 = 81.71 : x
  2. Step 2: Convert to fraction form
    127.31/190.58 = 81.71/x
  3. Step 3: Cross multiply
    127.31x = 190.58 × 81.71
  4. Step 4: Simplify right side
    127.31x = 15,571.13
  5. Step 5: Solve for x
    x = 15,571.13/127.31
  6. Step 6: Final answer
    x = 122.31

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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.