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Finding the Fourth Proportional to 215.47, 323.09 and 78.49

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Solution

The fourth proportional to 215.47, 323.09 and 78.49 is: 117.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.47 : 323.09 = 78.49 : x
  2. Step 2: Convert to fraction form
    215.47/323.09 = 78.49/x
  3. Step 3: Cross multiply
    215.47x = 323.09 × 78.49
  4. Step 4: Simplify right side
    215.47x = 25,359.33
  5. Step 5: Solve for x
    x = 25,359.33/215.47
  6. Step 6: Final answer
    x = 117.69

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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.