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Finding the Fourth Proportional to 879.60, 1,319.40 and 809.20

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Solution

The fourth proportional to 879.60, 1,319.40 and 809.20 is: 1,213.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    879.60 : 1,319.40 = 809.20 : x
  2. Step 2: Convert to fraction form
    879.60/1,319.40 = 809.20/x
  3. Step 3: Cross multiply
    879.60x = 1,319.40 × 809.20
  4. Step 4: Simplify right side
    879.60x = 1,067,658.48
  5. Step 5: Solve for x
    x = 1,067,658.48/879.60
  6. Step 6: Final answer
    x = 1,213.80

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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.