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Finding the Fourth Proportional to 69.86, 105.17 and 57.78

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Solution

The fourth proportional to 69.86, 105.17 and 57.78 is: 86.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    69.86 : 105.17 = 57.78 : x
  2. Step 2: Convert to fraction form
    69.86/105.17 = 57.78/x
  3. Step 3: Cross multiply
    69.86x = 105.17 × 57.78
  4. Step 4: Simplify right side
    69.86x = 6,076.43
  5. Step 5: Solve for x
    x = 6,076.43/69.86
  6. Step 6: Final answer
    x = 86.98

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.