Finding the Fourth Proportional to 1,813.68, 2,716.20 and 990.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,813.68 : 2,716.20 = 990.72 : x
2. Step 2: Convert to fraction form
   1,813.68/2,716.20 = 990.72/x
3. Step 3: Cross multiply
   1,813.68x = 2,716.20 × 990.72
4. Step 4: Simplify right side
   1,813.68x = 2,690,993.66
5. Step 5: Solve for x
   x = 2,690,993.66/1,813.68
6. Step 6: Final answer
   x = 1,483.72