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Finding the Fourth Proportional to 857.20, 1,285.79 and 207.94

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Solution

The fourth proportional to 857.20, 1,285.79 and 207.94 is: 311.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.20 : 1,285.79 = 207.94 : x
  2. Step 2: Convert to fraction form
    857.20/1,285.79 = 207.94/x
  3. Step 3: Cross multiply
    857.20x = 1,285.79 × 207.94
  4. Step 4: Simplify right side
    857.20x = 267,364.48
  5. Step 5: Solve for x
    x = 267,364.48/857.20
  6. Step 6: Final answer
    x = 311.91

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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.