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Finding the Fourth Proportional to 20.80, 31.19 and 20.46

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Solution

The fourth proportional to 20.80, 31.19 and 20.46 is: 30.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.80 : 31.19 = 20.46 : x
  2. Step 2: Convert to fraction form
    20.80/31.19 = 20.46/x
  3. Step 3: Cross multiply
    20.80x = 31.19 × 20.46
  4. Step 4: Simplify right side
    20.80x = 638.15
  5. Step 5: Solve for x
    x = 638.15/20.80
  6. Step 6: Final answer
    x = 30.68

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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.