Finding the Fourth Proportional to 1,420.71, 1,960.49 and 791.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,420.71 : 1,960.49 = 791.21 : x
2. Step 2: Convert to fraction form
   1,420.71/1,960.49 = 791.21/x
3. Step 3: Cross multiply
   1,420.71x = 1,960.49 × 791.21
4. Step 4: Simplify right side
   1,420.71x = 1,551,159.29
5. Step 5: Solve for x
   x = 1,551,159.29/1,420.71
6. Step 6: Final answer
   x = 1,091.82