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Finding the Fourth Proportional to 68.90, 103.36 and 20.82

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Solution

The fourth proportional to 68.90, 103.36 and 20.82 is: 31.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    68.90 : 103.36 = 20.82 : x
  2. Step 2: Convert to fraction form
    68.90/103.36 = 20.82/x
  3. Step 3: Cross multiply
    68.90x = 103.36 × 20.82
  4. Step 4: Simplify right side
    68.90x = 2,151.96
  5. Step 5: Solve for x
    x = 2,151.96/68.90
  6. Step 6: Final answer
    x = 31.23

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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.