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Finding the Fourth Proportional to 77.13, 115.12 and 66.81

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Solution

The fourth proportional to 77.13, 115.12 and 66.81 is: 99.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.13 : 115.12 = 66.81 : x
  2. Step 2: Convert to fraction form
    77.13/115.12 = 66.81/x
  3. Step 3: Cross multiply
    77.13x = 115.12 × 66.81
  4. Step 4: Simplify right side
    77.13x = 7,691.00
  5. Step 5: Solve for x
    x = 7,691.00/77.13
  6. Step 6: Final answer
    x = 99.71

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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.