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Finding the Fourth Proportional to 853.13, 1,278.39 and 505.78

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Solution

The fourth proportional to 853.13, 1,278.39 and 505.78 is: 757.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    853.13 : 1,278.39 = 505.78 : x
  2. Step 2: Convert to fraction form
    853.13/1,278.39 = 505.78/x
  3. Step 3: Cross multiply
    853.13x = 1,278.39 × 505.78
  4. Step 4: Simplify right side
    853.13x = 646,584.09
  5. Step 5: Solve for x
    x = 646,584.09/853.13
  6. Step 6: Final answer
    x = 757.90

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.