Finding the Fourth Proportional to 1,128.63, 1,557.58 and 631.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.63 : 1,557.58 = 631.34 : x
2. Step 2: Convert to fraction form
   1,128.63/1,557.58 = 631.34/x
3. Step 3: Cross multiply
   1,128.63x = 1,557.58 × 631.34
4. Step 4: Simplify right side
   1,128.63x = 983,362.56
5. Step 5: Solve for x
   x = 983,362.56/1,128.63
6. Step 6: Final answer
   x = 871.29