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Finding the Fourth Proportional to 172.68, 238.56 and 128.96

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Solution

The fourth proportional to 172.68, 238.56 and 128.96 is: 178.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    172.68 : 238.56 = 128.96 : x
  2. Step 2: Convert to fraction form
    172.68/238.56 = 128.96/x
  3. Step 3: Cross multiply
    172.68x = 238.56 × 128.96
  4. Step 4: Simplify right side
    172.68x = 30,764.70
  5. Step 5: Solve for x
    x = 30,764.70/172.68
  6. Step 6: Final answer
    x = 178.16

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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.