Finding the Fourth Proportional to 1,399.89, 1,931.82 and 876.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,399.89 : 1,931.82 = 876.21 : x
2. Step 2: Convert to fraction form
   1,399.89/1,931.82 = 876.21/x
3. Step 3: Cross multiply
   1,399.89x = 1,931.82 × 876.21
4. Step 4: Simplify right side
   1,399.89x = 1,692,680.00
5. Step 5: Solve for x
   x = 1,692,680.00/1,399.89
6. Step 6: Final answer
   x = 1,209.15