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Finding the Fourth Proportional to 172.55, 258.71 and 81.34

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Solution

The fourth proportional to 172.55, 258.71 and 81.34 is: 121.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.55 : 258.71 = 81.34 : x
  2. Step 2: Convert to fraction form
    172.55/258.71 = 81.34/x
  3. Step 3: Cross multiply
    172.55x = 258.71 × 81.34
  4. Step 4: Simplify right side
    172.55x = 21,043.47
  5. Step 5: Solve for x
    x = 21,043.47/172.55
  6. Step 6: Final answer
    x = 121.96

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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.