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Finding the Fourth Proportional to 87.96, 120.97 and 85.40

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Solution

The fourth proportional to 87.96, 120.97 and 85.40 is: 117.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.96 : 120.97 = 85.40 : x
  2. Step 2: Convert to fraction form
    87.96/120.97 = 85.40/x
  3. Step 3: Cross multiply
    87.96x = 120.97 × 85.40
  4. Step 4: Simplify right side
    87.96x = 10,330.84
  5. Step 5: Solve for x
    x = 10,330.84/87.96
  6. Step 6: Final answer
    x = 117.45

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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.