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Finding the Fourth Proportional to 129.86, 179.28 and 121.76

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Solution

The fourth proportional to 129.86, 179.28 and 121.76 is: 168.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.86 : 179.28 = 121.76 : x
  2. Step 2: Convert to fraction form
    129.86/179.28 = 121.76/x
  3. Step 3: Cross multiply
    129.86x = 179.28 × 121.76
  4. Step 4: Simplify right side
    129.86x = 21,829.13
  5. Step 5: Solve for x
    x = 21,829.13/129.86
  6. Step 6: Final answer
    x = 168.10

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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.