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Finding the Fourth Proportional to 111.25, 166.90 and 42.78

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Solution

The fourth proportional to 111.25, 166.90 and 42.78 is: 64.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    111.25 : 166.90 = 42.78 : x
  2. Step 2: Convert to fraction form
    111.25/166.90 = 42.78/x
  3. Step 3: Cross multiply
    111.25x = 166.90 × 42.78
  4. Step 4: Simplify right side
    111.25x = 7,139.88
  5. Step 5: Solve for x
    x = 7,139.88/111.25
  6. Step 6: Final answer
    x = 64.18

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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.