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Finding the Fourth Proportional to 879.72, 1,211.76 and 774.78

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Solution

The fourth proportional to 879.72, 1,211.76 and 774.78 is: 1,067.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    879.72 : 1,211.76 = 774.78 : x
  2. Step 2: Convert to fraction form
    879.72/1,211.76 = 774.78/x
  3. Step 3: Cross multiply
    879.72x = 1,211.76 × 774.78
  4. Step 4: Simplify right side
    879.72x = 938,847.41
  5. Step 5: Solve for x
    x = 938,847.41/879.72
  6. Step 6: Final answer
    x = 1,067.21

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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.