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Finding the Fourth Proportional to 131.14, 180.66 and 121.78

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Solution

The fourth proportional to 131.14, 180.66 and 121.78 is: 167.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    131.14 : 180.66 = 121.78 : x
  2. Step 2: Convert to fraction form
    131.14/180.66 = 121.78/x
  3. Step 3: Cross multiply
    131.14x = 180.66 × 121.78
  4. Step 4: Simplify right side
    131.14x = 22,000.77
  5. Step 5: Solve for x
    x = 22,000.77/131.14
  6. Step 6: Final answer
    x = 167.77

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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.