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Finding the Fourth Proportional to 857.81, 1,286.82 and 280.69

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Solution

The fourth proportional to 857.81, 1,286.82 and 280.69 is: 421.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.81 : 1,286.82 = 280.69 : x
  2. Step 2: Convert to fraction form
    857.81/1,286.82 = 280.69/x
  3. Step 3: Cross multiply
    857.81x = 1,286.82 × 280.69
  4. Step 4: Simplify right side
    857.81x = 361,194.29
  5. Step 5: Solve for x
    x = 361,194.29/857.81
  6. Step 6: Final answer
    x = 421.06

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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.