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Finding the Fourth Proportional to 87.08, 129.85 and 85.98

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Solution

The fourth proportional to 87.08, 129.85 and 85.98 is: 128.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.08 : 129.85 = 85.98 : x
  2. Step 2: Convert to fraction form
    87.08/129.85 = 85.98/x
  3. Step 3: Cross multiply
    87.08x = 129.85 × 85.98
  4. Step 4: Simplify right side
    87.08x = 11,164.50
  5. Step 5: Solve for x
    x = 11,164.50/87.08
  6. Step 6: Final answer
    x = 128.21

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.