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Finding the Fourth Proportional to 63.69, 87.90 and 47.31

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Solution

The fourth proportional to 63.69, 87.90 and 47.31 is: 65.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    63.69 : 87.90 = 47.31 : x
  2. Step 2: Convert to fraction form
    63.69/87.90 = 47.31/x
  3. Step 3: Cross multiply
    63.69x = 87.90 × 47.31
  4. Step 4: Simplify right side
    63.69x = 4,158.55
  5. Step 5: Solve for x
    x = 4,158.55/63.69
  6. Step 6: Final answer
    x = 65.29

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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.