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Finding the Fourth Proportional to 769.61, 1,059.91 and 720.20

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Solution

The fourth proportional to 769.61, 1,059.91 and 720.20 is: 991.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    769.61 : 1,059.91 = 720.20 : x
  2. Step 2: Convert to fraction form
    769.61/1,059.91 = 720.20/x
  3. Step 3: Cross multiply
    769.61x = 1,059.91 × 720.20
  4. Step 4: Simplify right side
    769.61x = 763,348.03
  5. Step 5: Solve for x
    x = 763,348.03/769.61
  6. Step 6: Final answer
    x = 991.86

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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.