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Finding the Fourth Proportional to 1,310.89, 1,809.12 and 721.43

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Solution

The fourth proportional to 1,310.89, 1,809.12 and 721.43 is: 995.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,310.89 : 1,809.12 = 721.43 : x
  2. Step 2: Convert to fraction form
    1,310.89/1,809.12 = 721.43/x
  3. Step 3: Cross multiply
    1,310.89x = 1,809.12 × 721.43
  4. Step 4: Simplify right side
    1,310.89x = 1,305,153.44
  5. Step 5: Solve for x
    x = 1,305,153.44/1,310.89
  6. Step 6: Final answer
    x = 995.62

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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.