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Finding the Fourth Proportional to 137.80, 190.12 and 78.79

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Solution

The fourth proportional to 137.80, 190.12 and 78.79 is: 108.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.80 : 190.12 = 78.79 : x
  2. Step 2: Convert to fraction form
    137.80/190.12 = 78.79/x
  3. Step 3: Cross multiply
    137.80x = 190.12 × 78.79
  4. Step 4: Simplify right side
    137.80x = 14,978.60
  5. Step 5: Solve for x
    x = 14,978.60/137.80
  6. Step 6: Final answer
    x = 108.70

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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.