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Finding the Fourth Proportional to 807.98, 1,115.88 and 721.05

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Solution

The fourth proportional to 807.98, 1,115.88 and 721.05 is: 995.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    807.98 : 1,115.88 = 721.05 : x
  2. Step 2: Convert to fraction form
    807.98/1,115.88 = 721.05/x
  3. Step 3: Cross multiply
    807.98x = 1,115.88 × 721.05
  4. Step 4: Simplify right side
    807.98x = 804,604.66
  5. Step 5: Solve for x
    x = 804,604.66/807.98
  6. Step 6: Final answer
    x = 995.83

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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.