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Finding the Fourth Proportional to 87.53, 130.99 and 81.38

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Solution

The fourth proportional to 87.53, 130.99 and 81.38 is: 121.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.53 : 130.99 = 81.38 : x
  2. Step 2: Convert to fraction form
    87.53/130.99 = 81.38/x
  3. Step 3: Cross multiply
    87.53x = 130.99 × 81.38
  4. Step 4: Simplify right side
    87.53x = 10,660.10
  5. Step 5: Solve for x
    x = 10,660.10/87.53
  6. Step 6: Final answer
    x = 121.79

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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.