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Finding the Fourth Proportional to 215.75, 324.17 and 138.75

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Solution

The fourth proportional to 215.75, 324.17 and 138.75 is: 208.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    215.75 : 324.17 = 138.75 : x
  2. Step 2: Convert to fraction form
    215.75/324.17 = 138.75/x
  3. Step 3: Cross multiply
    215.75x = 324.17 × 138.75
  4. Step 4: Simplify right side
    215.75x = 44,977.89
  5. Step 5: Solve for x
    x = 44,977.89/215.75
  6. Step 6: Final answer
    x = 208.48

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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.