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Finding the Fourth Proportional to 87.75, 130.86 and 85.77

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Solution

The fourth proportional to 87.75, 130.86 and 85.77 is: 127.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.75 : 130.86 = 85.77 : x
  2. Step 2: Convert to fraction form
    87.75/130.86 = 85.77/x
  3. Step 3: Cross multiply
    87.75x = 130.86 × 85.77
  4. Step 4: Simplify right side
    87.75x = 11,223.86
  5. Step 5: Solve for x
    x = 11,223.86/87.75
  6. Step 6: Final answer
    x = 127.91

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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.