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Finding the Fourth Proportional to 671.49, 1,007.11 and 209.21

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Solution

The fourth proportional to 671.49, 1,007.11 and 209.21 is: 313.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    671.49 : 1,007.11 = 209.21 : x
  2. Step 2: Convert to fraction form
    671.49/1,007.11 = 209.21/x
  3. Step 3: Cross multiply
    671.49x = 1,007.11 × 209.21
  4. Step 4: Simplify right side
    671.49x = 210,697.48
  5. Step 5: Solve for x
    x = 210,697.48/671.49
  6. Step 6: Final answer
    x = 313.78

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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.