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Finding the Fourth Proportional to 87.40, 130.74 and 85.54

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Solution

The fourth proportional to 87.40, 130.74 and 85.54 is: 127.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.40 : 130.74 = 85.54 : x
  2. Step 2: Convert to fraction form
    87.40/130.74 = 85.54/x
  3. Step 3: Cross multiply
    87.40x = 130.74 × 85.54
  4. Step 4: Simplify right side
    87.40x = 11,183.50
  5. Step 5: Solve for x
    x = 11,183.50/87.40
  6. Step 6: Final answer
    x = 127.96

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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.