Finding the Fourth Proportional to 1,428.13, 1,970.61 and 798.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,428.13 : 1,970.61 = 798.57 : x
2. Step 2: Convert to fraction form
   1,428.13/1,970.61 = 798.57/x
3. Step 3: Cross multiply
   1,428.13x = 1,970.61 × 798.57
4. Step 4: Simplify right side
   1,428.13x = 1,573,670.03
5. Step 5: Solve for x
   x = 1,573,670.03/1,428.13
6. Step 6: Final answer
   x = 1,101.91