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Finding the Fourth Proportional to 81.99, 122.33 and 81.50

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Solution

The fourth proportional to 81.99, 122.33 and 81.50 is: 121.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.99 : 122.33 = 81.50 : x
  2. Step 2: Convert to fraction form
    81.99/122.33 = 81.50/x
  3. Step 3: Cross multiply
    81.99x = 122.33 × 81.50
  4. Step 4: Simplify right side
    81.99x = 9,968.88
  5. Step 5: Solve for x
    x = 9,968.88/81.99
  6. Step 6: Final answer
    x = 121.59

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.