Finding the Fourth Proportional to 1,096.61, 1,639.91 and 819.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,096.61 : 1,639.91 = 819.15 : x
2. Step 2: Convert to fraction form
   1,096.61/1,639.91 = 819.15/x
3. Step 3: Cross multiply
   1,096.61x = 1,639.91 × 819.15
4. Step 4: Simplify right side
   1,096.61x = 1,343,332.28
5. Step 5: Solve for x
   x = 1,343,332.28/1,096.61
6. Step 6: Final answer
   x = 1,224.99