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Finding the Fourth Proportional to 20.65, 28.50 and 13.39

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Solution

The fourth proportional to 20.65, 28.50 and 13.39 is: 18.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.65 : 28.50 = 13.39 : x
  2. Step 2: Convert to fraction form
    20.65/28.50 = 13.39/x
  3. Step 3: Cross multiply
    20.65x = 28.50 × 13.39
  4. Step 4: Simplify right side
    20.65x = 381.62
  5. Step 5: Solve for x
    x = 381.62/20.65
  6. Step 6: Final answer
    x = 18.48

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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.