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Finding the Fourth Proportional to 111, 166.50 and 86.61

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Solution

The fourth proportional to 111, 166.50 and 86.61 is: 129.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    111 : 166.50 = 86.61 : x
  2. Step 2: Convert to fraction form
    111/166.50 = 86.61/x
  3. Step 3: Cross multiply
    111x = 166.50 × 86.61
  4. Step 4: Simplify right side
    111x = 14,420.57
  5. Step 5: Solve for x
    x = 14,420.57/111
  6. Step 6: Final answer
    x = 129.92

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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.