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Finding the Fourth Proportional to 128.56, 177.60 and 104.08

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Solution

The fourth proportional to 128.56, 177.60 and 104.08 is: 143.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.56 : 177.60 = 104.08 : x
  2. Step 2: Convert to fraction form
    128.56/177.60 = 104.08/x
  3. Step 3: Cross multiply
    128.56x = 177.60 × 104.08
  4. Step 4: Simplify right side
    128.56x = 18,484.61
  5. Step 5: Solve for x
    x = 18,484.61/128.56
  6. Step 6: Final answer
    x = 143.78

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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.