Finding the Fourth Proportional to 1,389.17, 2,082.72 and 841.22

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.17 : 2,082.72 = 841.22 : x
2. Step 2: Convert to fraction form
   1,389.17/2,082.72 = 841.22/x
3. Step 3: Cross multiply
   1,389.17x = 2,082.72 × 841.22
4. Step 4: Simplify right side
   1,389.17x = 1,752,025.72
5. Step 5: Solve for x
   x = 1,752,025.72/1,389.17
6. Step 6: Final answer
   x = 1,261.20