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Finding the Fourth Proportional to 127.31, 190.88 and 78.57

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Solution

The fourth proportional to 127.31, 190.88 and 78.57 is: 117.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    127.31 : 190.88 = 78.57 : x
  2. Step 2: Convert to fraction form
    127.31/190.88 = 78.57/x
  3. Step 3: Cross multiply
    127.31x = 190.88 × 78.57
  4. Step 4: Simplify right side
    127.31x = 14,997.34
  5. Step 5: Solve for x
    x = 14,997.34/127.31
  6. Step 6: Final answer
    x = 117.81

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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.