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Finding the Fourth Proportional to 857.86, 1,286.74 and 418.94

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Solution

The fourth proportional to 857.86, 1,286.74 and 418.94 is: 628.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.86 : 1,286.74 = 418.94 : x
  2. Step 2: Convert to fraction form
    857.86/1,286.74 = 418.94/x
  3. Step 3: Cross multiply
    857.86x = 1,286.74 × 418.94
  4. Step 4: Simplify right side
    857.86x = 539,070.60
  5. Step 5: Solve for x
    x = 539,070.60/857.86
  6. Step 6: Final answer
    x = 628.39

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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.