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Finding the Fourth Proportional to 111.79, 154.20 and 80.74

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Solution

The fourth proportional to 111.79, 154.20 and 80.74 is: 111.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    111.79 : 154.20 = 80.74 : x
  2. Step 2: Convert to fraction form
    111.79/154.20 = 80.74/x
  3. Step 3: Cross multiply
    111.79x = 154.20 × 80.74
  4. Step 4: Simplify right side
    111.79x = 12,450.11
  5. Step 5: Solve for x
    x = 12,450.11/111.79
  6. Step 6: Final answer
    x = 111.37

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.