Finding the Fourth Proportional to 1,561.72, 2,155.16 and 863.08

Step by Step Solution

1. Step 1: Write the proportion equation
   1,561.72 : 2,155.16 = 863.08 : x
2. Step 2: Convert to fraction form
   1,561.72/2,155.16 = 863.08/x
3. Step 3: Cross multiply
   1,561.72x = 2,155.16 × 863.08
4. Step 4: Simplify right side
   1,561.72x = 1,860,075.49
5. Step 5: Solve for x
   x = 1,860,075.49/1,561.72
6. Step 6: Final answer
   x = 1,191.04