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Finding the Fourth Proportional to 87.96, 121.23 and 66.15

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Solution

The fourth proportional to 87.96, 121.23 and 66.15 is: 91.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.96 : 121.23 = 66.15 : x
  2. Step 2: Convert to fraction form
    87.96/121.23 = 66.15/x
  3. Step 3: Cross multiply
    87.96x = 121.23 × 66.15
  4. Step 4: Simplify right side
    87.96x = 8,019.36
  5. Step 5: Solve for x
    x = 8,019.36/87.96
  6. Step 6: Final answer
    x = 91.17

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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.