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Finding the Fourth Proportional to 172.53, 258.84 and 81.20

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Solution

The fourth proportional to 172.53, 258.84 and 81.20 is: 121.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.53 : 258.84 = 81.20 : x
  2. Step 2: Convert to fraction form
    172.53/258.84 = 81.20/x
  3. Step 3: Cross multiply
    172.53x = 258.84 × 81.20
  4. Step 4: Simplify right side
    172.53x = 21,018.46
  5. Step 5: Solve for x
    x = 21,018.46/172.53
  6. Step 6: Final answer
    x = 121.82

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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.