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Finding the Fourth Proportional to 128.38, 177 and 104.80

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Solution

The fourth proportional to 128.38, 177 and 104.80 is: 144.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.38 : 177 = 104.80 : x
  2. Step 2: Convert to fraction form
    128.38/177 = 104.80/x
  3. Step 3: Cross multiply
    128.38x = 177 × 104.80
  4. Step 4: Simplify right side
    128.38x = 18,549.60
  5. Step 5: Solve for x
    x = 18,549.60/128.38
  6. Step 6: Final answer
    x = 144.49

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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.