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Finding the Fourth Proportional to 128.89, 177.85 and 76.44

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Solution

The fourth proportional to 128.89, 177.85 and 76.44 is: 105.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.89 : 177.85 = 76.44 : x
  2. Step 2: Convert to fraction form
    128.89/177.85 = 76.44/x
  3. Step 3: Cross multiply
    128.89x = 177.85 × 76.44
  4. Step 4: Simplify right side
    128.89x = 13,594.85
  5. Step 5: Solve for x
    x = 13,594.85/128.89
  6. Step 6: Final answer
    x = 105.48

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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.