Finding the Fourth Proportional to 1,124.78, 1,685.84 and 638.16

Step by Step Solution

1. Step 1: Write the proportion equation
   1,124.78 : 1,685.84 = 638.16 : x
2. Step 2: Convert to fraction form
   1,124.78/1,685.84 = 638.16/x
3. Step 3: Cross multiply
   1,124.78x = 1,685.84 × 638.16
4. Step 4: Simplify right side
   1,124.78x = 1,075,832.46
5. Step 5: Solve for x
   x = 1,075,832.46/1,124.78
6. Step 6: Final answer
   x = 956.49