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Finding the Fourth Proportional to 128.56, 193.08 and 115.12

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Solution

The fourth proportional to 128.56, 193.08 and 115.12 is: 172.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.56 : 193.08 = 115.12 : x
  2. Step 2: Convert to fraction form
    128.56/193.08 = 115.12/x
  3. Step 3: Cross multiply
    128.56x = 193.08 × 115.12
  4. Step 4: Simplify right side
    128.56x = 22,227.37
  5. Step 5: Solve for x
    x = 22,227.37/128.56
  6. Step 6: Final answer
    x = 172.89

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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.