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Finding the Fourth Proportional to 128.87, 177.84 and 76.41

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Solution

The fourth proportional to 128.87, 177.84 and 76.41 is: 105.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.87 : 177.84 = 76.41 : x
  2. Step 2: Convert to fraction form
    128.87/177.84 = 76.41/x
  3. Step 3: Cross multiply
    128.87x = 177.84 × 76.41
  4. Step 4: Simplify right side
    128.87x = 13,588.75
  5. Step 5: Solve for x
    x = 13,588.75/128.87
  6. Step 6: Final answer
    x = 105.44

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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.