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Finding the Fourth Proportional to 86.06, 129.20 and 71.79

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Solution

The fourth proportional to 86.06, 129.20 and 71.79 is: 107.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.06 : 129.20 = 71.79 : x
  2. Step 2: Convert to fraction form
    86.06/129.20 = 71.79/x
  3. Step 3: Cross multiply
    86.06x = 129.20 × 71.79
  4. Step 4: Simplify right side
    86.06x = 9,274.42
  5. Step 5: Solve for x
    x = 9,274.42/86.06
  6. Step 6: Final answer
    x = 107.76

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.