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Finding the Fourth Proportional to 879.20, 1,318.80 and 828.80

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Solution

The fourth proportional to 879.20, 1,318.80 and 828.80 is: 1,243.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    879.20 : 1,318.80 = 828.80 : x
  2. Step 2: Convert to fraction form
    879.20/1,318.80 = 828.80/x
  3. Step 3: Cross multiply
    879.20x = 1,318.80 × 828.80
  4. Step 4: Simplify right side
    879.20x = 1,093,021.44
  5. Step 5: Solve for x
    x = 1,093,021.44/879.20
  6. Step 6: Final answer
    x = 1,243.20

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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.