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Finding the Fourth Proportional to 172.49, 258.74 and 138.21

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Solution

The fourth proportional to 172.49, 258.74 and 138.21 is: 207.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.49 : 258.74 = 138.21 : x
  2. Step 2: Convert to fraction form
    172.49/258.74 = 138.21/x
  3. Step 3: Cross multiply
    172.49x = 258.74 × 138.21
  4. Step 4: Simplify right side
    172.49x = 35,759.76
  5. Step 5: Solve for x
    x = 35,759.76/172.49
  6. Step 6: Final answer
    x = 207.32

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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.