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Finding the Fourth Proportional to 63, 86.91 and 39.69

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Solution

The fourth proportional to 63, 86.91 and 39.69 is: 54.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    63 : 86.91 = 39.69 : x
  2. Step 2: Convert to fraction form
    63/86.91 = 39.69/x
  3. Step 3: Cross multiply
    63x = 86.91 × 39.69
  4. Step 4: Simplify right side
    63x = 3,449.46
  5. Step 5: Solve for x
    x = 3,449.46/63
  6. Step 6: Final answer
    x = 54.75

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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.