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Finding the Fourth Proportional to 81.51, 122.10 and 42.95

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Solution

The fourth proportional to 81.51, 122.10 and 42.95 is: 64.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.51 : 122.10 = 42.95 : x
  2. Step 2: Convert to fraction form
    81.51/122.10 = 42.95/x
  3. Step 3: Cross multiply
    81.51x = 122.10 × 42.95
  4. Step 4: Simplify right side
    81.51x = 5,243.58
  5. Step 5: Solve for x
    x = 5,243.58/81.51
  6. Step 6: Final answer
    x = 64.33

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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.