Finding the Fourth Proportional to 1,131.38, 1,561.31 and 633.99

Step by Step Solution

1. Step 1: Write the proportion equation
   1,131.38 : 1,561.31 = 633.99 : x
2. Step 2: Convert to fraction form
   1,131.38/1,561.31 = 633.99/x
3. Step 3: Cross multiply
   1,131.38x = 1,561.31 × 633.99
4. Step 4: Simplify right side
   1,131.38x = 989,854.93
5. Step 5: Solve for x
   x = 989,854.93/1,131.38
6. Step 6: Final answer
   x = 874.91