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Finding the Fourth Proportional to 206.47, 309.83 and 78.31

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Solution

The fourth proportional to 206.47, 309.83 and 78.31 is: 117.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.47 : 309.83 = 78.31 : x
  2. Step 2: Convert to fraction form
    206.47/309.83 = 78.31/x
  3. Step 3: Cross multiply
    206.47x = 309.83 × 78.31
  4. Step 4: Simplify right side
    206.47x = 24,262.79
  5. Step 5: Solve for x
    x = 24,262.79/206.47
  6. Step 6: Final answer
    x = 117.51

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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.