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Finding the Fourth Proportional to 20.62, 30.90 and 13

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Solution

The fourth proportional to 20.62, 30.90 and 13 is: 19.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.62 : 30.90 = 13 : x
  2. Step 2: Convert to fraction form
    20.62/30.90 = 13/x
  3. Step 3: Cross multiply
    20.62x = 30.90 × 13
  4. Step 4: Simplify right side
    20.62x = 401.70
  5. Step 5: Solve for x
    x = 401.70/20.62
  6. Step 6: Final answer
    x = 19.48

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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.