Finding the Fourth Proportional to 1,131.57, 1,561.48 and 634.20

Step by Step Solution

1. Step 1: Write the proportion equation
   1,131.57 : 1,561.48 = 634.20 : x
2. Step 2: Convert to fraction form
   1,131.57/1,561.48 = 634.20/x
3. Step 3: Cross multiply
   1,131.57x = 1,561.48 × 634.20
4. Step 4: Simplify right side
   1,131.57x = 990,290.62
5. Step 5: Solve for x
   x = 990,290.62/1,131.57
6. Step 6: Final answer
   x = 875.15