Finding the Fourth Proportional to 2,661.84, 3,993.00 and 813.15

Step by Step Solution

1. Step 1: Write the proportion equation
   2,661.84 : 3,993.00 = 813.15 : x
2. Step 2: Convert to fraction form
   2,661.84/3,993.00 = 813.15/x
3. Step 3: Cross multiply
   2,661.84x = 3,993.00 × 813.15
4. Step 4: Simplify right side
   2,661.84x = 3,246,904.90
5. Step 5: Solve for x
   x = 3,246,904.90/2,661.84
6. Step 6: Final answer
   x = 1,219.80