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Finding the Fourth Proportional to 82.21, 123.86 and 81.26

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Solution

The fourth proportional to 82.21, 123.86 and 81.26 is: 122.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    82.21 : 123.86 = 81.26 : x
  2. Step 2: Convert to fraction form
    82.21/123.86 = 81.26/x
  3. Step 3: Cross multiply
    82.21x = 123.86 × 81.26
  4. Step 4: Simplify right side
    82.21x = 10,064.86
  5. Step 5: Solve for x
    x = 10,064.86/82.21
  6. Step 6: Final answer
    x = 122.43

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.