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Finding the Fourth Proportional to 213.12, 319.68 and 68.88

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Solution

The fourth proportional to 213.12, 319.68 and 68.88 is: 103.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    213.12 : 319.68 = 68.88 : x
  2. Step 2: Convert to fraction form
    213.12/319.68 = 68.88/x
  3. Step 3: Cross multiply
    213.12x = 319.68 × 68.88
  4. Step 4: Simplify right side
    213.12x = 22,019.56
  5. Step 5: Solve for x
    x = 22,019.56/213.12
  6. Step 6: Final answer
    x = 103.32

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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.