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Finding the Fourth Proportional to 81.51, 122.21 and 54.07

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Solution

The fourth proportional to 81.51, 122.21 and 54.07 is: 81.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.51 : 122.21 = 54.07 : x
  2. Step 2: Convert to fraction form
    81.51/122.21 = 54.07/x
  3. Step 3: Cross multiply
    81.51x = 122.21 × 54.07
  4. Step 4: Simplify right side
    81.51x = 6,607.52
  5. Step 5: Solve for x
    x = 6,607.52/81.51
  6. Step 6: Final answer
    x = 81.07

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.