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Finding the Fourth Proportional to 128.31, 177.08 and 75.87

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Solution

The fourth proportional to 128.31, 177.08 and 75.87 is: 104.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.31 : 177.08 = 75.87 : x
  2. Step 2: Convert to fraction form
    128.31/177.08 = 75.87/x
  3. Step 3: Cross multiply
    128.31x = 177.08 × 75.87
  4. Step 4: Simplify right side
    128.31x = 13,435.06
  5. Step 5: Solve for x
    x = 13,435.06/128.31
  6. Step 6: Final answer
    x = 104.71

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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.