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Finding the Fourth Proportional to 321.10, 481.20 and 128.50

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Solution

The fourth proportional to 321.10, 481.20 and 128.50 is: 192.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    321.10 : 481.20 = 128.50 : x
  2. Step 2: Convert to fraction form
    321.10/481.20 = 128.50/x
  3. Step 3: Cross multiply
    321.10x = 481.20 × 128.50
  4. Step 4: Simplify right side
    321.10x = 61,834.20
  5. Step 5: Solve for x
    x = 61,834.20/321.10
  6. Step 6: Final answer
    x = 192.57

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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.