Finding the Fourth Proportional to 1,111.68, 1,664.16 and 839.04

Step by Step Solution

1. Step 1: Write the proportion equation
   1,111.68 : 1,664.16 = 839.04 : x
2. Step 2: Convert to fraction form
   1,111.68/1,664.16 = 839.04/x
3. Step 3: Cross multiply
   1,111.68x = 1,664.16 × 839.04
4. Step 4: Simplify right side
   1,111.68x = 1,396,296.81
5. Step 5: Solve for x
   x = 1,396,296.81/1,111.68
6. Step 6: Final answer
   x = 1,256.02