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Finding the Fourth Proportional to 80.94, 111.72 and 66.42

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Solution

The fourth proportional to 80.94, 111.72 and 66.42 is: 91.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.94 : 111.72 = 66.42 : x
  2. Step 2: Convert to fraction form
    80.94/111.72 = 66.42/x
  3. Step 3: Cross multiply
    80.94x = 111.72 × 66.42
  4. Step 4: Simplify right side
    80.94x = 7,420.44
  5. Step 5: Solve for x
    x = 7,420.44/80.94
  6. Step 6: Final answer
    x = 91.68

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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.