Finding the Fourth Proportional to 1,380.40, 1,905.72 and 876.94

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.40 : 1,905.72 = 876.94 : x
2. Step 2: Convert to fraction form
   1,380.40/1,905.72 = 876.94/x
3. Step 3: Cross multiply
   1,380.40x = 1,905.72 × 876.94
4. Step 4: Simplify right side
   1,380.40x = 1,671,202.10
5. Step 5: Solve for x
   x = 1,671,202.10/1,380.40
6. Step 6: Final answer
   x = 1,210.67