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Finding the Fourth Proportional to 172.16, 258.39 and 80.91

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Solution

The fourth proportional to 172.16, 258.39 and 80.91 is: 121.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.16 : 258.39 = 80.91 : x
  2. Step 2: Convert to fraction form
    172.16/258.39 = 80.91/x
  3. Step 3: Cross multiply
    172.16x = 258.39 × 80.91
  4. Step 4: Simplify right side
    172.16x = 20,906.33
  5. Step 5: Solve for x
    x = 20,906.33/172.16
  6. Step 6: Final answer
    x = 121.44

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.