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Finding the Fourth Proportional to 63.75, 87.99 and 39.21

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Solution

The fourth proportional to 63.75, 87.99 and 39.21 is: 54.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    63.75 : 87.99 = 39.21 : x
  2. Step 2: Convert to fraction form
    63.75/87.99 = 39.21/x
  3. Step 3: Cross multiply
    63.75x = 87.99 × 39.21
  4. Step 4: Simplify right side
    63.75x = 3,449.86
  5. Step 5: Solve for x
    x = 3,449.86/63.75
  6. Step 6: Final answer
    x = 54.11

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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.