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Finding the Fourth Proportional to 87.18, 130.82 and 80

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Solution

The fourth proportional to 87.18, 130.82 and 80 is: 120.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.18 : 130.82 = 80 : x
  2. Step 2: Convert to fraction form
    87.18/130.82 = 80/x
  3. Step 3: Cross multiply
    87.18x = 130.82 × 80
  4. Step 4: Simplify right side
    87.18x = 10,465.60
  5. Step 5: Solve for x
    x = 10,465.60/87.18
  6. Step 6: Final answer
    x = 120.05

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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.