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Finding the Fourth Proportional to 81.35, 122.00 and 42.88

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Solution

The fourth proportional to 81.35, 122.00 and 42.88 is: 64.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.35 : 122.00 = 42.88 : x
  2. Step 2: Convert to fraction form
    81.35/122.00 = 42.88/x
  3. Step 3: Cross multiply
    81.35x = 122.00 × 42.88
  4. Step 4: Simplify right side
    81.35x = 5,230.84
  5. Step 5: Solve for x
    x = 5,230.84/81.35
  6. Step 6: Final answer
    x = 64.30

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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.