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Finding the Fourth Proportional to 206.58, 309.72 and 138.38

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Solution

The fourth proportional to 206.58, 309.72 and 138.38 is: 207.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.58 : 309.72 = 138.38 : x
  2. Step 2: Convert to fraction form
    206.58/309.72 = 138.38/x
  3. Step 3: Cross multiply
    206.58x = 309.72 × 138.38
  4. Step 4: Simplify right side
    206.58x = 42,859.05
  5. Step 5: Solve for x
    x = 42,859.05/206.58
  6. Step 6: Final answer
    x = 207.47

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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.