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Finding the Fourth Proportional to 128.32, 177.39 and 122.88

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Solution

The fourth proportional to 128.32, 177.39 and 122.88 is: 169.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.32 : 177.39 = 122.88 : x
  2. Step 2: Convert to fraction form
    128.32/177.39 = 122.88/x
  3. Step 3: Cross multiply
    128.32x = 177.39 × 122.88
  4. Step 4: Simplify right side
    128.32x = 21,798.35
  5. Step 5: Solve for x
    x = 21,798.35/128.32
  6. Step 6: Final answer
    x = 169.88

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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.