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Finding the Fourth Proportional to 128.44, 177.20 and 89.68

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Solution

The fourth proportional to 128.44, 177.20 and 89.68 is: 123.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.44 : 177.20 = 89.68 : x
  2. Step 2: Convert to fraction form
    128.44/177.20 = 89.68/x
  3. Step 3: Cross multiply
    128.44x = 177.20 × 89.68
  4. Step 4: Simplify right side
    128.44x = 15,891.30
  5. Step 5: Solve for x
    x = 15,891.30/128.44
  6. Step 6: Final answer
    x = 123.73

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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.