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Finding the Fourth Proportional to 128.89, 178.03 and 116.61

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Solution

The fourth proportional to 128.89, 178.03 and 116.61 is: 161.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.89 : 178.03 = 116.61 : x
  2. Step 2: Convert to fraction form
    128.89/178.03 = 116.61/x
  3. Step 3: Cross multiply
    128.89x = 178.03 × 116.61
  4. Step 4: Simplify right side
    128.89x = 20,760.08
  5. Step 5: Solve for x
    x = 20,760.08/128.89
  6. Step 6: Final answer
    x = 161.07

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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.