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Finding the Fourth Proportional to 812.60, 1,126.55 and 768.80

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Solution

The fourth proportional to 812.60, 1,126.55 and 768.80 is: 1,065.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.60 : 1,126.55 = 768.80 : x
  2. Step 2: Convert to fraction form
    812.60/1,126.55 = 768.80/x
  3. Step 3: Cross multiply
    812.60x = 1,126.55 × 768.80
  4. Step 4: Simplify right side
    812.60x = 866,091.64
  5. Step 5: Solve for x
    x = 866,091.64/812.60
  6. Step 6: Final answer
    x = 1,065.83

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.