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Finding the Fourth Proportional to 206.69, 309.99 and 69.80

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Solution

The fourth proportional to 206.69, 309.99 and 69.80 is: 104.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.69 : 309.99 = 69.80 : x
  2. Step 2: Convert to fraction form
    206.69/309.99 = 69.80/x
  3. Step 3: Cross multiply
    206.69x = 309.99 × 69.80
  4. Step 4: Simplify right side
    206.69x = 21,637.30
  5. Step 5: Solve for x
    x = 21,637.30/206.69
  6. Step 6: Final answer
    x = 104.68

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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.