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Finding the Fourth Proportional to 89.09, 122.82 and 87.15

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Solution

The fourth proportional to 89.09, 122.82 and 87.15 is: 120.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.09 : 122.82 = 87.15 : x
  2. Step 2: Convert to fraction form
    89.09/122.82 = 87.15/x
  3. Step 3: Cross multiply
    89.09x = 122.82 × 87.15
  4. Step 4: Simplify right side
    89.09x = 10,704.29
  5. Step 5: Solve for x
    x = 10,704.29/89.09
  6. Step 6: Final answer
    x = 120.15

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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.