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Finding the Fourth Proportional to 212.20, 318.09 and 67.81

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Solution

The fourth proportional to 212.20, 318.09 and 67.81 is: 101.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.20 : 318.09 = 67.81 : x
  2. Step 2: Convert to fraction form
    212.20/318.09 = 67.81/x
  3. Step 3: Cross multiply
    212.20x = 318.09 × 67.81
  4. Step 4: Simplify right side
    212.20x = 21,569.68
  5. Step 5: Solve for x
    x = 21,569.68/212.20
  6. Step 6: Final answer
    x = 101.65

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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.