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Finding the Fourth Proportional to 323.85, 485.45 and 128.78

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Solution

The fourth proportional to 323.85, 485.45 and 128.78 is: 193.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    323.85 : 485.45 = 128.78 : x
  2. Step 2: Convert to fraction form
    323.85/485.45 = 128.78/x
  3. Step 3: Cross multiply
    323.85x = 485.45 × 128.78
  4. Step 4: Simplify right side
    323.85x = 62,515.61
  5. Step 5: Solve for x
    x = 62,515.61/323.85
  6. Step 6: Final answer
    x = 193.04

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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.