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Finding the Fourth Proportional to 80.81, 111.42 and 64.42

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Solution

The fourth proportional to 80.81, 111.42 and 64.42 is: 88.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.81 : 111.42 = 64.42 : x
  2. Step 2: Convert to fraction form
    80.81/111.42 = 64.42/x
  3. Step 3: Cross multiply
    80.81x = 111.42 × 64.42
  4. Step 4: Simplify right side
    80.81x = 7,177.12
  5. Step 5: Solve for x
    x = 7,177.12/80.81
  6. Step 6: Final answer
    x = 88.81

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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.