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Finding the Fourth Proportional to 769.90, 1,062.49 and 420.61

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Solution

The fourth proportional to 769.90, 1,062.49 and 420.61 is: 580.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    769.90 : 1,062.49 = 420.61 : x
  2. Step 2: Convert to fraction form
    769.90/1,062.49 = 420.61/x
  3. Step 3: Cross multiply
    769.90x = 1,062.49 × 420.61
  4. Step 4: Simplify right side
    769.90x = 446,887.55
  5. Step 5: Solve for x
    x = 446,887.55/769.90
  6. Step 6: Final answer
    x = 580.45

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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.