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Finding the Fourth Proportional to 81.61, 122.51 and 45.56

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Solution

The fourth proportional to 81.61, 122.51 and 45.56 is: 68.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.61 : 122.51 = 45.56 : x
  2. Step 2: Convert to fraction form
    81.61/122.51 = 45.56/x
  3. Step 3: Cross multiply
    81.61x = 122.51 × 45.56
  4. Step 4: Simplify right side
    81.61x = 5,581.98
  5. Step 5: Solve for x
    x = 5,581.98/81.61
  6. Step 6: Final answer
    x = 68.40

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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.