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Finding the Fourth Proportional to 206.64, 309.96 and 138.06

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Solution

The fourth proportional to 206.64, 309.96 and 138.06 is: 207.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.64 : 309.96 = 138.06 : x
  2. Step 2: Convert to fraction form
    206.64/309.96 = 138.06/x
  3. Step 3: Cross multiply
    206.64x = 309.96 × 138.06
  4. Step 4: Simplify right side
    206.64x = 42,793.08
  5. Step 5: Solve for x
    x = 42,793.08/206.64
  6. Step 6: Final answer
    x = 207.09

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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.