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Finding the Fourth Proportional to 87.55, 120.90 and 65.68

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Solution

The fourth proportional to 87.55, 120.90 and 65.68 is: 90.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.55 : 120.90 = 65.68 : x
  2. Step 2: Convert to fraction form
    87.55/120.90 = 65.68/x
  3. Step 3: Cross multiply
    87.55x = 120.90 × 65.68
  4. Step 4: Simplify right side
    87.55x = 7,940.16
  5. Step 5: Solve for x
    x = 7,940.16/87.55
  6. Step 6: Final answer
    x = 90.70

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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.