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Finding the Fourth Proportional to 86.16, 129 and 71.66

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Solution

The fourth proportional to 86.16, 129 and 71.66 is: 107.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.16 : 129 = 71.66 : x
  2. Step 2: Convert to fraction form
    86.16/129 = 71.66/x
  3. Step 3: Cross multiply
    86.16x = 129 × 71.66
  4. Step 4: Simplify right side
    86.16x = 9,244.14
  5. Step 5: Solve for x
    x = 9,244.14/86.16
  6. Step 6: Final answer
    x = 107.29

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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.