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Finding the Fourth Proportional to 769.89, 1,062.42 and 420.57

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Solution

The fourth proportional to 769.89, 1,062.42 and 420.57 is: 580.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    769.89 : 1,062.42 = 420.57 : x
  2. Step 2: Convert to fraction form
    769.89/1,062.42 = 420.57/x
  3. Step 3: Cross multiply
    769.89x = 1,062.42 × 420.57
  4. Step 4: Simplify right side
    769.89x = 446,821.98
  5. Step 5: Solve for x
    x = 446,821.98/769.89
  6. Step 6: Final answer
    x = 580.37

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.