Finding the Fourth Proportional to 1,399.78, 2,099.94 and 784.18

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.78 : 2,099.94 = 784.18 : x
2. Step 2: Convert to fraction form
   1,399.78/2,099.94 = 784.18/x
3. Step 3: Cross multiply
   1,399.78x = 2,099.94 × 784.18
4. Step 4: Simplify right side
   1,399.78x = 1,646,730.95
5. Step 5: Solve for x
   x = 1,646,730.95/1,399.78
6. Step 6: Final answer
   x = 1,176.42