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Finding the Third Proportional to 81.42 and 90.42

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Solution

The third proportional to 81.42 and 90.42 is: 100.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.42 : 90.42 = 90.42 : x
  2. Step 2: Convert to fraction form
    81.42/90.42 = 90.42/x
  3. Step 3: Cross multiply
    81.42x = 90.42 × 90.42
  4. Step 4: Simplify right side
    81.42x = 8,176.12
  5. Step 5: Solve for x
    x = 8,176.12/81.42
  6. Step 6: Final answer
    x = 100.42

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Why These Related Problems?

These problems maintain the same ratio (1.11) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.