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Finding the Fourth Proportional to 769.68, 1,146.78 and 720

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Solution

The fourth proportional to 769.68, 1,146.78 and 720 is: 1,072.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    769.68 : 1,146.78 = 720 : x
  2. Step 2: Convert to fraction form
    769.68/1,146.78 = 720/x
  3. Step 3: Cross multiply
    769.68x = 1,146.78 × 720
  4. Step 4: Simplify right side
    769.68x = 825,681.60
  5. Step 5: Solve for x
    x = 825,681.60/769.68
  6. Step 6: Final answer
    x = 1,072.76

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.