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Finding the Fourth Proportional to 20.84, 31.18 and 12.76

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Solution

The fourth proportional to 20.84, 31.18 and 12.76 is: 19.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.84 : 31.18 = 12.76 : x
  2. Step 2: Convert to fraction form
    20.84/31.18 = 12.76/x
  3. Step 3: Cross multiply
    20.84x = 31.18 × 12.76
  4. Step 4: Simplify right side
    20.84x = 397.86
  5. Step 5: Solve for x
    x = 397.86/20.84
  6. Step 6: Final answer
    x = 19.09

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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.