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Finding the Fourth Proportional to 129.79, 179.20 and 80.68

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Solution

The fourth proportional to 129.79, 179.20 and 80.68 is: 111.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.79 : 179.20 = 80.68 : x
  2. Step 2: Convert to fraction form
    129.79/179.20 = 80.68/x
  3. Step 3: Cross multiply
    129.79x = 179.20 × 80.68
  4. Step 4: Simplify right side
    129.79x = 14,457.86
  5. Step 5: Solve for x
    x = 14,457.86/129.79
  6. Step 6: Final answer
    x = 111.39

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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.