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Finding the Fourth Proportional to 172.10, 257.99 and 80.85

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Solution

The fourth proportional to 172.10, 257.99 and 80.85 is: 121.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.10 : 257.99 = 80.85 : x
  2. Step 2: Convert to fraction form
    172.10/257.99 = 80.85/x
  3. Step 3: Cross multiply
    172.10x = 257.99 × 80.85
  4. Step 4: Simplify right side
    172.10x = 20,858.09
  5. Step 5: Solve for x
    x = 20,858.09/172.10
  6. Step 6: Final answer
    x = 121.20

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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.