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Finding the Fourth Proportional to 105.61, 158.21 and 81.71

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Solution

The fourth proportional to 105.61, 158.21 and 81.71 is: 122.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.61 : 158.21 = 81.71 : x
  2. Step 2: Convert to fraction form
    105.61/158.21 = 81.71/x
  3. Step 3: Cross multiply
    105.61x = 158.21 × 81.71
  4. Step 4: Simplify right side
    105.61x = 12,926.93
  5. Step 5: Solve for x
    x = 12,926.93/105.61
  6. Step 6: Final answer
    x = 122.41

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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.