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Finding the Fourth Proportional to 87.81, 131.72 and 42.17

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Solution

The fourth proportional to 87.81, 131.72 and 42.17 is: 63.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.81 : 131.72 = 42.17 : x
  2. Step 2: Convert to fraction form
    87.81/131.72 = 42.17/x
  3. Step 3: Cross multiply
    87.81x = 131.72 × 42.17
  4. Step 4: Simplify right side
    87.81x = 5,553.76
  5. Step 5: Solve for x
    x = 5,553.76/87.81
  6. Step 6: Final answer
    x = 63.25

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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.