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Finding the Fourth Proportional to 857.42, 1,286.32 and 280.34

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Solution

The fourth proportional to 857.42, 1,286.32 and 280.34 is: 420.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.42 : 1,286.32 = 280.34 : x
  2. Step 2: Convert to fraction form
    857.42/1,286.32 = 280.34/x
  3. Step 3: Cross multiply
    857.42x = 1,286.32 × 280.34
  4. Step 4: Simplify right side
    857.42x = 360,606.95
  5. Step 5: Solve for x
    x = 360,606.95/857.42
  6. Step 6: Final answer
    x = 420.57

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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.