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Finding the Fourth Proportional to 172.15, 257.83 and 80.71

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Solution

The fourth proportional to 172.15, 257.83 and 80.71 is: 120.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.15 : 257.83 = 80.71 : x
  2. Step 2: Convert to fraction form
    172.15/257.83 = 80.71/x
  3. Step 3: Cross multiply
    172.15x = 257.83 × 80.71
  4. Step 4: Simplify right side
    172.15x = 20,809.46
  5. Step 5: Solve for x
    x = 20,809.46/172.15
  6. Step 6: Final answer
    x = 120.88

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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.