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Finding the Fourth Proportional to 212.45, 316.31 and 209.41

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Solution

The fourth proportional to 212.45, 316.31 and 209.41 is: 311.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.45 : 316.31 = 209.41 : x
  2. Step 2: Convert to fraction form
    212.45/316.31 = 209.41/x
  3. Step 3: Cross multiply
    212.45x = 316.31 × 209.41
  4. Step 4: Simplify right side
    212.45x = 66,237.83
  5. Step 5: Solve for x
    x = 66,237.83/212.45
  6. Step 6: Final answer
    x = 311.78

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.