Finding the Fourth Proportional to 1,388.19, 1,915.71 and 798.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.19 : 1,915.71 = 798.72 : x
2. Step 2: Convert to fraction form
   1,388.19/1,915.71 = 798.72/x
3. Step 3: Cross multiply
   1,388.19x = 1,915.71 × 798.72
4. Step 4: Simplify right side
   1,388.19x = 1,530,106.31
5. Step 5: Solve for x
   x = 1,530,106.31/1,388.19
6. Step 6: Final answer
   x = 1,102.24