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Finding the Fourth Proportional to 68.81, 103.22 and 20.72

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Solution

The fourth proportional to 68.81, 103.22 and 20.72 is: 31.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    68.81 : 103.22 = 20.72 : x
  2. Step 2: Convert to fraction form
    68.81/103.22 = 20.72/x
  3. Step 3: Cross multiply
    68.81x = 103.22 × 20.72
  4. Step 4: Simplify right side
    68.81x = 2,138.72
  5. Step 5: Solve for x
    x = 2,138.72/68.81
  6. Step 6: Final answer
    x = 31.08

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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.