Finding the Fourth Proportional to 1,380.84, 1,905.52 and 790.96

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.84 : 1,905.52 = 790.96 : x
2. Step 2: Convert to fraction form
   1,380.84/1,905.52 = 790.96/x
3. Step 3: Cross multiply
   1,380.84x = 1,905.52 × 790.96
4. Step 4: Simplify right side
   1,380.84x = 1,507,190.10
5. Step 5: Solve for x
   x = 1,507,190.10/1,380.84
6. Step 6: Final answer
   x = 1,091.50