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Finding the Fourth Proportional to 206.10, 309.15 and 69.21

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Solution

The fourth proportional to 206.10, 309.15 and 69.21 is: 103.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.10 : 309.15 = 69.21 : x
  2. Step 2: Convert to fraction form
    206.10/309.15 = 69.21/x
  3. Step 3: Cross multiply
    206.10x = 309.15 × 69.21
  4. Step 4: Simplify right side
    206.10x = 21,396.27
  5. Step 5: Solve for x
    x = 21,396.27/206.10
  6. Step 6: Final answer
    x = 103.82

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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.