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Finding the Fourth Proportional to 81.81, 122.08 and 72.70

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Solution

The fourth proportional to 81.81, 122.08 and 72.70 is: 108.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.81 : 122.08 = 72.70 : x
  2. Step 2: Convert to fraction form
    81.81/122.08 = 72.70/x
  3. Step 3: Cross multiply
    81.81x = 122.08 × 72.70
  4. Step 4: Simplify right side
    81.81x = 8,875.22
  5. Step 5: Solve for x
    x = 8,875.22/81.81
  6. Step 6: Final answer
    x = 108.49

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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.