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Finding the Fourth Proportional to 87.89, 121.10 and 66.02

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Solution

The fourth proportional to 87.89, 121.10 and 66.02 is: 90.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.89 : 121.10 = 66.02 : x
  2. Step 2: Convert to fraction form
    87.89/121.10 = 66.02/x
  3. Step 3: Cross multiply
    87.89x = 121.10 × 66.02
  4. Step 4: Simplify right side
    87.89x = 7,994.09
  5. Step 5: Solve for x
    x = 7,994.09/87.89
  6. Step 6: Final answer
    x = 90.96

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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.