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Finding the Fourth Proportional to 127.31, 190.74 and 78.50

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Solution

The fourth proportional to 127.31, 190.74 and 78.50 is: 117.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    127.31 : 190.74 = 78.50 : x
  2. Step 2: Convert to fraction form
    127.31/190.74 = 78.50/x
  3. Step 3: Cross multiply
    127.31x = 190.74 × 78.50
  4. Step 4: Simplify right side
    127.31x = 14,972.14
  5. Step 5: Solve for x
    x = 14,972.14/127.31
  6. Step 6: Final answer
    x = 117.61

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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.