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Finding the Fourth Proportional to 519.80, 779.70 and 447.80

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Solution

The fourth proportional to 519.80, 779.70 and 447.80 is: 671.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    519.80 : 779.70 = 447.80 : x
  2. Step 2: Convert to fraction form
    519.80/779.70 = 447.80/x
  3. Step 3: Cross multiply
    519.80x = 779.70 × 447.80
  4. Step 4: Simplify right side
    519.80x = 349,149.66
  5. Step 5: Solve for x
    x = 349,149.66/519.80
  6. Step 6: Final answer
    x = 671.70

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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.