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Finding the Fourth Proportional to 76.84, 105.98 and 63.78

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Solution

The fourth proportional to 76.84, 105.98 and 63.78 is: 87.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.84 : 105.98 = 63.78 : x
  2. Step 2: Convert to fraction form
    76.84/105.98 = 63.78/x
  3. Step 3: Cross multiply
    76.84x = 105.98 × 63.78
  4. Step 4: Simplify right side
    76.84x = 6,759.40
  5. Step 5: Solve for x
    x = 6,759.40/76.84
  6. Step 6: Final answer
    x = 87.97

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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.