Finding the Fourth Proportional to 1,123.10, 1,681.68 and 878.48

Step by Step Solution

1. Step 1: Write the proportion equation
   1,123.10 : 1,681.68 = 878.48 : x
2. Step 2: Convert to fraction form
   1,123.10/1,681.68 = 878.48/x
3. Step 3: Cross multiply
   1,123.10x = 1,681.68 × 878.48
4. Step 4: Simplify right side
   1,123.10x = 1,477,322.25
5. Step 5: Solve for x
   x = 1,477,322.25/1,123.10
6. Step 6: Final answer
   x = 1,315.40