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Finding the Fourth Proportional to 77.82, 107.15 and 66.72

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Solution

The fourth proportional to 77.82, 107.15 and 66.72 is: 91.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.82 : 107.15 = 66.72 : x
  2. Step 2: Convert to fraction form
    77.82/107.15 = 66.72/x
  3. Step 3: Cross multiply
    77.82x = 107.15 × 66.72
  4. Step 4: Simplify right side
    77.82x = 7,149.05
  5. Step 5: Solve for x
    x = 7,149.05/77.82
  6. Step 6: Final answer
    x = 91.87

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.