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Finding the Fourth Proportional to 87.21, 130.71 and 85.19

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Solution

The fourth proportional to 87.21, 130.71 and 85.19 is: 127.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.21 : 130.71 = 85.19 : x
  2. Step 2: Convert to fraction form
    87.21/130.71 = 85.19/x
  3. Step 3: Cross multiply
    87.21x = 130.71 × 85.19
  4. Step 4: Simplify right side
    87.21x = 11,134.85
  5. Step 5: Solve for x
    x = 11,134.85/87.21
  6. Step 6: Final answer
    x = 127.68

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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.