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Finding the Fourth Proportional to 111.45, 166.91 and 78.87

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Solution

The fourth proportional to 111.45, 166.91 and 78.87 is: 118.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    111.45 : 166.91 = 78.87 : x
  2. Step 2: Convert to fraction form
    111.45/166.91 = 78.87/x
  3. Step 3: Cross multiply
    111.45x = 166.91 × 78.87
  4. Step 4: Simplify right side
    111.45x = 13,163.80
  5. Step 5: Solve for x
    x = 13,163.80/111.45
  6. Step 6: Final answer
    x = 118.11

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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.