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Finding the Fourth Proportional to 415.21, 621.97 and 209.49

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Solution

The fourth proportional to 415.21, 621.97 and 209.49 is: 313.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    415.21 : 621.97 = 209.49 : x
  2. Step 2: Convert to fraction form
    415.21/621.97 = 209.49/x
  3. Step 3: Cross multiply
    415.21x = 621.97 × 209.49
  4. Step 4: Simplify right side
    415.21x = 130,295.45
  5. Step 5: Solve for x
    x = 130,295.45/415.21
  6. Step 6: Final answer
    x = 313.81

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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.