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Finding the Fourth Proportional to 172.31, 257.49 and 139.39

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Solution

The fourth proportional to 172.31, 257.49 and 139.39 is: 208.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.31 : 257.49 = 139.39 : x
  2. Step 2: Convert to fraction form
    172.31/257.49 = 139.39/x
  3. Step 3: Cross multiply
    172.31x = 257.49 × 139.39
  4. Step 4: Simplify right side
    172.31x = 35,890.89
  5. Step 5: Solve for x
    x = 35,890.89/172.31
  6. Step 6: Final answer
    x = 208.30

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.