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Finding the Fourth Proportional to 782.41, 1,079.31 and 634.78

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Solution

The fourth proportional to 782.41, 1,079.31 and 634.78 is: 875.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.41 : 1,079.31 = 634.78 : x
  2. Step 2: Convert to fraction form
    782.41/1,079.31 = 634.78/x
  3. Step 3: Cross multiply
    782.41x = 1,079.31 × 634.78
  4. Step 4: Simplify right side
    782.41x = 685,121.23
  5. Step 5: Solve for x
    x = 685,121.23/782.41
  6. Step 6: Final answer
    x = 875.66

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.