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Finding the Fourth Proportional to 215.40, 323.21 and 105.78

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Solution

The fourth proportional to 215.40, 323.21 and 105.78 is: 158.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.40 : 323.21 = 105.78 : x
  2. Step 2: Convert to fraction form
    215.40/323.21 = 105.78/x
  3. Step 3: Cross multiply
    215.40x = 323.21 × 105.78
  4. Step 4: Simplify right side
    215.40x = 34,188.62
  5. Step 5: Solve for x
    x = 34,188.62/215.40
  6. Step 6: Final answer
    x = 158.72

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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.