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Finding the Fourth Proportional to 215.31, 322.97 and 78.38

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Solution

The fourth proportional to 215.31, 322.97 and 78.38 is: 117.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.31 : 322.97 = 78.38 : x
  2. Step 2: Convert to fraction form
    215.31/322.97 = 78.38/x
  3. Step 3: Cross multiply
    215.31x = 322.97 × 78.38
  4. Step 4: Simplify right side
    215.31x = 25,312.38
  5. Step 5: Solve for x
    x = 25,312.38/215.31
  6. Step 6: Final answer
    x = 117.56

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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.