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Finding the Fourth Proportional to 87.49, 120.89 and 64.25

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Solution

The fourth proportional to 87.49, 120.89 and 64.25 is: 88.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.49 : 120.89 = 64.25 : x
  2. Step 2: Convert to fraction form
    87.49/120.89 = 64.25/x
  3. Step 3: Cross multiply
    87.49x = 120.89 × 64.25
  4. Step 4: Simplify right side
    87.49x = 7,767.18
  5. Step 5: Solve for x
    x = 7,767.18/87.49
  6. Step 6: Final answer
    x = 88.78

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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.