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Finding the Fourth Proportional to 20.62, 31.10 and 20.40

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Solution

The fourth proportional to 20.62, 31.10 and 20.40 is: 30.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.62 : 31.10 = 20.40 : x
  2. Step 2: Convert to fraction form
    20.62/31.10 = 20.40/x
  3. Step 3: Cross multiply
    20.62x = 31.10 × 20.40
  4. Step 4: Simplify right side
    20.62x = 634.44
  5. Step 5: Solve for x
    x = 634.44/20.62
  6. Step 6: Final answer
    x = 30.77

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.