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Finding the Fourth Proportional to 853.70, 1,278.74 and 391.86

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Solution

The fourth proportional to 853.70, 1,278.74 and 391.86 is: 586.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    853.70 : 1,278.74 = 391.86 : x
  2. Step 2: Convert to fraction form
    853.70/1,278.74 = 391.86/x
  3. Step 3: Cross multiply
    853.70x = 1,278.74 × 391.86
  4. Step 4: Simplify right side
    853.70x = 501,087.06
  5. Step 5: Solve for x
    x = 501,087.06/853.70
  6. Step 6: Final answer
    x = 586.96

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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.