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Finding the Fourth Proportional to 1,029.78, 1,420.74 and 679.86

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Solution

The fourth proportional to 1,029.78, 1,420.74 and 679.86 is: 937.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,029.78 : 1,420.74 = 679.86 : x
  2. Step 2: Convert to fraction form
    1,029.78/1,420.74 = 679.86/x
  3. Step 3: Cross multiply
    1,029.78x = 1,420.74 × 679.86
  4. Step 4: Simplify right side
    1,029.78x = 965,904.30
  5. Step 5: Solve for x
    x = 965,904.30/1,029.78
  6. Step 6: Final answer
    x = 937.97

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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.