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Finding the Fourth Proportional to 20.66, 30.80 and 19.12

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Solution

The fourth proportional to 20.66, 30.80 and 19.12 is: 28.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.66 : 30.80 = 19.12 : x
  2. Step 2: Convert to fraction form
    20.66/30.80 = 19.12/x
  3. Step 3: Cross multiply
    20.66x = 30.80 × 19.12
  4. Step 4: Simplify right side
    20.66x = 588.90
  5. Step 5: Solve for x
    x = 588.90/20.66
  6. Step 6: Final answer
    x = 28.50

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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.