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Finding the Fourth Proportional to 206.21, 309.31 and 84.47

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Solution

The fourth proportional to 206.21, 309.31 and 84.47 is: 126.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.21 : 309.31 = 84.47 : x
  2. Step 2: Convert to fraction form
    206.21/309.31 = 84.47/x
  3. Step 3: Cross multiply
    206.21x = 309.31 × 84.47
  4. Step 4: Simplify right side
    206.21x = 26,127.87
  5. Step 5: Solve for x
    x = 26,127.87/206.21
  6. Step 6: Final answer
    x = 126.70

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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.