Finding the Fourth Proportional to 1,131.08, 1,560.72 and 688.90

Step by Step Solution

1. Step 1: Write the proportion equation
   1,131.08 : 1,560.72 = 688.90 : x
2. Step 2: Convert to fraction form
   1,131.08/1,560.72 = 688.90/x
3. Step 3: Cross multiply
   1,131.08x = 1,560.72 × 688.90
4. Step 4: Simplify right side
   1,131.08x = 1,075,180.01
5. Step 5: Solve for x
   x = 1,075,180.01/1,131.08
6. Step 6: Final answer
   x = 950.58