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Finding the Fourth Proportional to 63.78, 87.98 and 47.39

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Solution

The fourth proportional to 63.78, 87.98 and 47.39 is: 65.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    63.78 : 87.98 = 47.39 : x
  2. Step 2: Convert to fraction form
    63.78/87.98 = 47.39/x
  3. Step 3: Cross multiply
    63.78x = 87.98 × 47.39
  4. Step 4: Simplify right side
    63.78x = 4,168.70
  5. Step 5: Solve for x
    x = 4,168.70/63.78
  6. Step 6: Final answer
    x = 65.36

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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.