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Finding the Fourth Proportional to 172.45, 258.52 and 85.73

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Solution

The fourth proportional to 172.45, 258.52 and 85.73 is: 128.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.45 : 258.52 = 85.73 : x
  2. Step 2: Convert to fraction form
    172.45/258.52 = 85.73/x
  3. Step 3: Cross multiply
    172.45x = 258.52 × 85.73
  4. Step 4: Simplify right side
    172.45x = 22,163.51
  5. Step 5: Solve for x
    x = 22,163.51/172.45
  6. Step 6: Final answer
    x = 128.52

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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.