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Finding the Fourth Proportional to 857.38, 1,285.74 and 510.78

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Solution

The fourth proportional to 857.38, 1,285.74 and 510.78 is: 765.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.38 : 1,285.74 = 510.78 : x
  2. Step 2: Convert to fraction form
    857.38/1,285.74 = 510.78/x
  3. Step 3: Cross multiply
    857.38x = 1,285.74 × 510.78
  4. Step 4: Simplify right side
    857.38x = 656,730.28
  5. Step 5: Solve for x
    x = 656,730.28/857.38
  6. Step 6: Final answer
    x = 765.97

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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.