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Finding the Fourth Proportional to 20.83, 31.21 and 13.69

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Solution

The fourth proportional to 20.83, 31.21 and 13.69 is: 20.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.83 : 31.21 = 13.69 : x
  2. Step 2: Convert to fraction form
    20.83/31.21 = 13.69/x
  3. Step 3: Cross multiply
    20.83x = 31.21 × 13.69
  4. Step 4: Simplify right side
    20.83x = 427.15
  5. Step 5: Solve for x
    x = 427.15/20.83
  6. Step 6: Final answer
    x = 20.51

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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.