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Finding the Fourth Proportional to 89.07, 122.90 and 87.72

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Solution

The fourth proportional to 89.07, 122.90 and 87.72 is: 121.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.07 : 122.90 = 87.72 : x
  2. Step 2: Convert to fraction form
    89.07/122.90 = 87.72/x
  3. Step 3: Cross multiply
    89.07x = 122.90 × 87.72
  4. Step 4: Simplify right side
    89.07x = 10,780.35
  5. Step 5: Solve for x
    x = 10,780.35/89.07
  6. Step 6: Final answer
    x = 121.03

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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.