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Finding the Fourth Proportional to 320.75, 481.32 and 128.39

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Solution

The fourth proportional to 320.75, 481.32 and 128.39 is: 192.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    320.75 : 481.32 = 128.39 : x
  2. Step 2: Convert to fraction form
    320.75/481.32 = 128.39/x
  3. Step 3: Cross multiply
    320.75x = 481.32 × 128.39
  4. Step 4: Simplify right side
    320.75x = 61,796.67
  5. Step 5: Solve for x
    x = 61,796.67/320.75
  6. Step 6: Final answer
    x = 192.66

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.