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Finding the Fourth Proportional to 129.78, 179.19 and 86.22

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Solution

The fourth proportional to 129.78, 179.19 and 86.22 is: 119.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.78 : 179.19 = 86.22 : x
  2. Step 2: Convert to fraction form
    129.78/179.19 = 86.22/x
  3. Step 3: Cross multiply
    129.78x = 179.19 × 86.22
  4. Step 4: Simplify right side
    129.78x = 15,449.76
  5. Step 5: Solve for x
    x = 15,449.76/129.78
  6. Step 6: Final answer
    x = 119.05

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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.