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Finding the Fourth Proportional to 20.80, 31.03 and 19.11

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Solution

The fourth proportional to 20.80, 31.03 and 19.11 is: 28.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.80 : 31.03 = 19.11 : x
  2. Step 2: Convert to fraction form
    20.80/31.03 = 19.11/x
  3. Step 3: Cross multiply
    20.80x = 31.03 × 19.11
  4. Step 4: Simplify right side
    20.80x = 592.98
  5. Step 5: Solve for x
    x = 592.98/20.80
  6. Step 6: Final answer
    x = 28.51

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.