Finding the Fourth Proportional to 1,131.55, 1,561.47 and 634.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,131.55 : 1,561.47 = 634.21 : x
2. Step 2: Convert to fraction form
   1,131.55/1,561.47 = 634.21/x
3. Step 3: Cross multiply
   1,131.55x = 1,561.47 × 634.21
4. Step 4: Simplify right side
   1,131.55x = 990,299.89
5. Step 5: Solve for x
   x = 990,299.89/1,131.55
6. Step 6: Final answer
   x = 875.17