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Finding the Fourth Proportional to 89.19, 122.96 and 72.78

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Solution

The fourth proportional to 89.19, 122.96 and 72.78 is: 100.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.19 : 122.96 = 72.78 : x
  2. Step 2: Convert to fraction form
    89.19/122.96 = 72.78/x
  3. Step 3: Cross multiply
    89.19x = 122.96 × 72.78
  4. Step 4: Simplify right side
    89.19x = 8,948.66
  5. Step 5: Solve for x
    x = 8,948.66/89.19
  6. Step 6: Final answer
    x = 100.33

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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.