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Finding the Fourth Proportional to 131.12, 180.92 and 78.68

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Solution

The fourth proportional to 131.12, 180.92 and 78.68 is: 108.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    131.12 : 180.92 = 78.68 : x
  2. Step 2: Convert to fraction form
    131.12/180.92 = 78.68/x
  3. Step 3: Cross multiply
    131.12x = 180.92 × 78.68
  4. Step 4: Simplify right side
    131.12x = 14,233.49
  5. Step 5: Solve for x
    x = 14,233.49/131.12
  6. Step 6: Final answer
    x = 108.56

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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.