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Finding the Fourth Proportional to 72.11, 108 and 53.85

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Solution

The fourth proportional to 72.11, 108 and 53.85 is: 80.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.11 : 108 = 53.85 : x
  2. Step 2: Convert to fraction form
    72.11/108 = 53.85/x
  3. Step 3: Cross multiply
    72.11x = 108 × 53.85
  4. Step 4: Simplify right side
    72.11x = 5,816.21
  5. Step 5: Solve for x
    x = 5,816.21/72.11
  6. Step 6: Final answer
    x = 80.65

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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.