Finding the Fourth Proportional to 1,388.94, 1,916.78 and 829.84

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.94 : 1,916.78 = 829.84 : x
2. Step 2: Convert to fraction form
   1,388.94/1,916.78 = 829.84/x
3. Step 3: Cross multiply
   1,388.94x = 1,916.78 × 829.84
4. Step 4: Simplify right side
   1,388.94x = 1,590,620.72
5. Step 5: Solve for x
   x = 1,590,620.72/1,388.94
6. Step 6: Final answer
   x = 1,145.20