Finding the Fourth Proportional to 1,381.59, 1,905.80 and 909.63

Step by Step Solution

1. Step 1: Write the proportion equation
   1,381.59 : 1,905.80 = 909.63 : x
2. Step 2: Convert to fraction form
   1,381.59/1,905.80 = 909.63/x
3. Step 3: Cross multiply
   1,381.59x = 1,905.80 × 909.63
4. Step 4: Simplify right side
   1,381.59x = 1,733,568.31
5. Step 5: Solve for x
   x = 1,733,568.31/1,381.59
6. Step 6: Final answer
   x = 1,254.76