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Finding the Fourth Proportional to 63.87, 87.87 and 57.21

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Solution

The fourth proportional to 63.87, 87.87 and 57.21 is: 78.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    63.87 : 87.87 = 57.21 : x
  2. Step 2: Convert to fraction form
    63.87/87.87 = 57.21/x
  3. Step 3: Cross multiply
    63.87x = 87.87 × 57.21
  4. Step 4: Simplify right side
    63.87x = 5,027.04
  5. Step 5: Solve for x
    x = 5,027.04/63.87
  6. Step 6: Final answer
    x = 78.71

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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.