Finding the Fourth Proportional to 1,380.94, 1,905.98 and 909.59

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.94 : 1,905.98 = 909.59 : x
2. Step 2: Convert to fraction form
   1,380.94/1,905.98 = 909.59/x
3. Step 3: Cross multiply
   1,380.94x = 1,905.98 × 909.59
4. Step 4: Simplify right side
   1,380.94x = 1,733,664.79
5. Step 5: Solve for x
   x = 1,733,664.79/1,380.94
6. Step 6: Final answer
   x = 1,255.43