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Finding the Fourth Proportional to 76.86, 105.99 and 63.74

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Solution

The fourth proportional to 76.86, 105.99 and 63.74 is: 87.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.86 : 105.99 = 63.74 : x
  2. Step 2: Convert to fraction form
    76.86/105.99 = 63.74/x
  3. Step 3: Cross multiply
    76.86x = 105.99 × 63.74
  4. Step 4: Simplify right side
    76.86x = 6,755.27
  5. Step 5: Solve for x
    x = 6,755.27/76.86
  6. Step 6: Final answer
    x = 87.89

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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.