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Finding the Fourth Proportional to 42.65, 63.96 and 12.21

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Solution

The fourth proportional to 42.65, 63.96 and 12.21 is: 18.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.65 : 63.96 = 12.21 : x
  2. Step 2: Convert to fraction form
    42.65/63.96 = 12.21/x
  3. Step 3: Cross multiply
    42.65x = 63.96 × 12.21
  4. Step 4: Simplify right side
    42.65x = 780.89
  5. Step 5: Solve for x
    x = 780.89/42.65
  6. Step 6: Final answer
    x = 18.31

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.