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Finding the Fourth Proportional to 80.72, 111.42 and 61.12

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Solution

The fourth proportional to 80.72, 111.42 and 61.12 is: 84.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.72 : 111.42 = 61.12 : x
  2. Step 2: Convert to fraction form
    80.72/111.42 = 61.12/x
  3. Step 3: Cross multiply
    80.72x = 111.42 × 61.12
  4. Step 4: Simplify right side
    80.72x = 6,809.99
  5. Step 5: Solve for x
    x = 6,809.99/80.72
  6. Step 6: Final answer
    x = 84.37

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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.