Finding the Fourth Proportional to 1,428.37, 1,970.91 and 798.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,428.37 : 1,970.91 = 798.78 : x
2. Step 2: Convert to fraction form
   1,428.37/1,970.91 = 798.78/x
3. Step 3: Cross multiply
   1,428.37x = 1,970.91 × 798.78
4. Step 4: Simplify right side
   1,428.37x = 1,574,323.49
5. Step 5: Solve for x
   x = 1,574,323.49/1,428.37
6. Step 6: Final answer
   x = 1,102.18