Finding the Fourth Proportional to 1,373.19, 2,057.69 and 816.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,373.19 : 2,057.69 = 816.80 : x
2. Step 2: Convert to fraction form
   1,373.19/2,057.69 = 816.80/x
3. Step 3: Cross multiply
   1,373.19x = 2,057.69 × 816.80
4. Step 4: Simplify right side
   1,373.19x = 1,680,706.82
5. Step 5: Solve for x
   x = 1,680,706.82/1,373.19
6. Step 6: Final answer
   x = 1,223.94