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Finding the Fourth Proportional to 87.21, 120.36 and 49.87

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Solution

The fourth proportional to 87.21, 120.36 and 49.87 is: 68.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.21 : 120.36 = 49.87 : x
  2. Step 2: Convert to fraction form
    87.21/120.36 = 49.87/x
  3. Step 3: Cross multiply
    87.21x = 120.36 × 49.87
  4. Step 4: Simplify right side
    87.21x = 6,002.10
  5. Step 5: Solve for x
    x = 6,002.10/87.21
  6. Step 6: Final answer
    x = 68.82

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.