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Finding the Fourth Proportional to 215.85, 323.15 and 138.85

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Solution

The fourth proportional to 215.85, 323.15 and 138.85 is: 207.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.85 : 323.15 = 138.85 : x
  2. Step 2: Convert to fraction form
    215.85/323.15 = 138.85/x
  3. Step 3: Cross multiply
    215.85x = 323.15 × 138.85
  4. Step 4: Simplify right side
    215.85x = 44,870.21
  5. Step 5: Solve for x
    x = 44,870.21/215.85
  6. Step 6: Final answer
    x = 207.87

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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.