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Finding the Fourth Proportional to 86.79, 129.25 and 84.66

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Solution

The fourth proportional to 86.79, 129.25 and 84.66 is: 126.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.79 : 129.25 = 84.66 : x
  2. Step 2: Convert to fraction form
    86.79/129.25 = 84.66/x
  3. Step 3: Cross multiply
    86.79x = 129.25 × 84.66
  4. Step 4: Simplify right side
    86.79x = 10,942.31
  5. Step 5: Solve for x
    x = 10,942.31/86.79
  6. Step 6: Final answer
    x = 126.08

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.