Finding the Fourth Proportional to 3,987.83, 5,979.49 and 1,213.72

Step by Step Solution

1. Step 1: Write the proportion equation
   3,987.83 : 5,979.49 = 1,213.72 : x
2. Step 2: Convert to fraction form
   3,987.83/5,979.49 = 1,213.72/x
3. Step 3: Cross multiply
   3,987.83x = 5,979.49 × 1,213.72
4. Step 4: Simplify right side
   3,987.83x = 7,257,408.62
5. Step 5: Solve for x
   x = 7,257,408.62/3,987.83
6. Step 6: Final answer
   x = 1,819.89