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Finding the Fourth Proportional to 857.17, 1,285.31 and 394.55

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Solution

The fourth proportional to 857.17, 1,285.31 and 394.55 is: 591.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.17 : 1,285.31 = 394.55 : x
  2. Step 2: Convert to fraction form
    857.17/1,285.31 = 394.55/x
  3. Step 3: Cross multiply
    857.17x = 1,285.31 × 394.55
  4. Step 4: Simplify right side
    857.17x = 507,113.62
  5. Step 5: Solve for x
    x = 507,113.62/857.17
  6. Step 6: Final answer
    x = 591.62

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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.