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Finding the Fourth Proportional to 215.66, 323.39 and 78.61

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Solution

The fourth proportional to 215.66, 323.39 and 78.61 is: 117.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.66 : 323.39 = 78.61 : x
  2. Step 2: Convert to fraction form
    215.66/323.39 = 78.61/x
  3. Step 3: Cross multiply
    215.66x = 323.39 × 78.61
  4. Step 4: Simplify right side
    215.66x = 25,421.69
  5. Step 5: Solve for x
    x = 25,421.69/215.66
  6. Step 6: Final answer
    x = 117.88

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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.