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Finding the Fourth Proportional to 857.78, 1,286.51 and 418.59

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Solution

The fourth proportional to 857.78, 1,286.51 and 418.59 is: 627.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.78 : 1,286.51 = 418.59 : x
  2. Step 2: Convert to fraction form
    857.78/1,286.51 = 418.59/x
  3. Step 3: Cross multiply
    857.78x = 1,286.51 × 418.59
  4. Step 4: Simplify right side
    857.78x = 538,521.27
  5. Step 5: Solve for x
    x = 538,521.27/857.78
  6. Step 6: Final answer
    x = 627.81

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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.