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Finding the Fourth Proportional to 69.17, 103.78 and 21.08

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Solution

The fourth proportional to 69.17, 103.78 and 21.08 is: 31.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    69.17 : 103.78 = 21.08 : x
  2. Step 2: Convert to fraction form
    69.17/103.78 = 21.08/x
  3. Step 3: Cross multiply
    69.17x = 103.78 × 21.08
  4. Step 4: Simplify right side
    69.17x = 2,187.32
  5. Step 5: Solve for x
    x = 2,187.32/69.17
  6. Step 6: Final answer
    x = 31.62

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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.