Finding the Fourth Proportional to 1,222.10, 1,685.34 and 802.81

Step by Step Solution

1. Step 1: Write the proportion equation
   1,222.10 : 1,685.34 = 802.81 : x
2. Step 2: Convert to fraction form
   1,222.10/1,685.34 = 802.81/x
3. Step 3: Cross multiply
   1,222.10x = 1,685.34 × 802.81
4. Step 4: Simplify right side
   1,222.10x = 1,353,009.91
5. Step 5: Solve for x
   x = 1,353,009.91/1,222.10
6. Step 6: Final answer
   x = 1,107.12