Finding the Fourth Proportional to 1,399.68, 1,931.85 and 874.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.68 : 1,931.85 = 874.80 : x
2. Step 2: Convert to fraction form
   1,399.68/1,931.85 = 874.80/x
3. Step 3: Cross multiply
   1,399.68x = 1,931.85 × 874.80
4. Step 4: Simplify right side
   1,399.68x = 1,689,982.38
5. Step 5: Solve for x
   x = 1,689,982.38/1,399.68
6. Step 6: Final answer
   x = 1,207.41