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Finding the Fourth Proportional to 172.68, 238.56 and 128.94

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Solution

The fourth proportional to 172.68, 238.56 and 128.94 is: 178.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.68 : 238.56 = 128.94 : x
  2. Step 2: Convert to fraction form
    172.68/238.56 = 128.94/x
  3. Step 3: Cross multiply
    172.68x = 238.56 × 128.94
  4. Step 4: Simplify right side
    172.68x = 30,759.93
  5. Step 5: Solve for x
    x = 30,759.93/172.68
  6. Step 6: Final answer
    x = 178.13

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.