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Finding the Fourth Proportional to 685.94, 1,029.78 and 679.05

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Solution

The fourth proportional to 685.94, 1,029.78 and 679.05 is: 1,019.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.94 : 1,029.78 = 679.05 : x
  2. Step 2: Convert to fraction form
    685.94/1,029.78 = 679.05/x
  3. Step 3: Cross multiply
    685.94x = 1,029.78 × 679.05
  4. Step 4: Simplify right side
    685.94x = 699,272.11
  5. Step 5: Solve for x
    x = 699,272.11/685.94
  6. Step 6: Final answer
    x = 1,019.44

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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.