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Finding the Fourth Proportional to 321.32, 481.56 and 128.72

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Solution

The fourth proportional to 321.32, 481.56 and 128.72 is: 192.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.32 : 481.56 = 128.72 : x
  2. Step 2: Convert to fraction form
    321.32/481.56 = 128.72/x
  3. Step 3: Cross multiply
    321.32x = 481.56 × 128.72
  4. Step 4: Simplify right side
    321.32x = 61,986.40
  5. Step 5: Solve for x
    x = 61,986.40/321.32
  6. Step 6: Final answer
    x = 192.91

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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.