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Finding the Fourth Proportional to 111.14, 166.40 and 90.78

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Solution

The fourth proportional to 111.14, 166.40 and 90.78 is: 135.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    111.14 : 166.40 = 90.78 : x
  2. Step 2: Convert to fraction form
    111.14/166.40 = 90.78/x
  3. Step 3: Cross multiply
    111.14x = 166.40 × 90.78
  4. Step 4: Simplify right side
    111.14x = 15,105.79
  5. Step 5: Solve for x
    x = 15,105.79/111.14
  6. Step 6: Final answer
    x = 135.92

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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.