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Finding the Fourth Proportional to 87.21, 131.56 and 82.15

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Solution

The fourth proportional to 87.21, 131.56 and 82.15 is: 123.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.21 : 131.56 = 82.15 : x
  2. Step 2: Convert to fraction form
    87.21/131.56 = 82.15/x
  3. Step 3: Cross multiply
    87.21x = 131.56 × 82.15
  4. Step 4: Simplify right side
    87.21x = 10,807.12
  5. Step 5: Solve for x
    x = 10,807.12/87.21
  6. Step 6: Final answer
    x = 123.92

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.