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Finding the Fourth Proportional to 857.93, 1,286.93 and 280.80

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Solution

The fourth proportional to 857.93, 1,286.93 and 280.80 is: 421.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.93 : 1,286.93 = 280.80 : x
  2. Step 2: Convert to fraction form
    857.93/1,286.93 = 280.80/x
  3. Step 3: Cross multiply
    857.93x = 1,286.93 × 280.80
  4. Step 4: Simplify right side
    857.93x = 361,369.94
  5. Step 5: Solve for x
    x = 361,369.94/857.93
  6. Step 6: Final answer
    x = 421.21

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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.