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Finding the Fourth Proportional to 548.70, 821.61 and 420.54

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Solution

The fourth proportional to 548.70, 821.61 and 420.54 is: 629.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    548.70 : 821.61 = 420.54 : x
  2. Step 2: Convert to fraction form
    548.70/821.61 = 420.54/x
  3. Step 3: Cross multiply
    548.70x = 821.61 × 420.54
  4. Step 4: Simplify right side
    548.70x = 345,519.87
  5. Step 5: Solve for x
    x = 345,519.87/548.70
  6. Step 6: Final answer
    x = 629.71

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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.