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Finding the Fourth Proportional to 137.78, 190.13 and 78.76

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Solution

The fourth proportional to 137.78, 190.13 and 78.76 is: 108.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.78 : 190.13 = 78.76 : x
  2. Step 2: Convert to fraction form
    137.78/190.13 = 78.76/x
  3. Step 3: Cross multiply
    137.78x = 190.13 × 78.76
  4. Step 4: Simplify right side
    137.78x = 14,974.64
  5. Step 5: Solve for x
    x = 14,974.64/137.78
  6. Step 6: Final answer
    x = 108.69

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.