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Finding the Fourth Proportional to 172.31, 258.28 and 81.06

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Solution

The fourth proportional to 172.31, 258.28 and 81.06 is: 121.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.31 : 258.28 = 81.06 : x
  2. Step 2: Convert to fraction form
    172.31/258.28 = 81.06/x
  3. Step 3: Cross multiply
    172.31x = 258.28 × 81.06
  4. Step 4: Simplify right side
    172.31x = 20,936.18
  5. Step 5: Solve for x
    x = 20,936.18/172.31
  6. Step 6: Final answer
    x = 121.50

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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.