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Finding the Fourth Proportional to 63.50, 87.70 and 39

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Solution

The fourth proportional to 63.50, 87.70 and 39 is: 53.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    63.50 : 87.70 = 39 : x
  2. Step 2: Convert to fraction form
    63.50/87.70 = 39/x
  3. Step 3: Cross multiply
    63.50x = 87.70 × 39
  4. Step 4: Simplify right side
    63.50x = 3,420.30
  5. Step 5: Solve for x
    x = 3,420.30/63.50
  6. Step 6: Final answer
    x = 53.86

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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.