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Finding the Fourth Proportional to 857.15, 1,285.73 and 394.79

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Solution

The fourth proportional to 857.15, 1,285.73 and 394.79 is: 592.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.15 : 1,285.73 = 394.79 : x
  2. Step 2: Convert to fraction form
    857.15/1,285.73 = 394.79/x
  3. Step 3: Cross multiply
    857.15x = 1,285.73 × 394.79
  4. Step 4: Simplify right side
    857.15x = 507,584.94
  5. Step 5: Solve for x
    x = 507,584.94/857.15
  6. Step 6: Final answer
    x = 592.18

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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.