Finding the Fourth Proportional to 1,380.23, 1,904.73 and 790.77

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.23 : 1,904.73 = 790.77 : x
2. Step 2: Convert to fraction form
   1,380.23/1,904.73 = 790.77/x
3. Step 3: Cross multiply
   1,380.23x = 1,904.73 × 790.77
4. Step 4: Simplify right side
   1,380.23x = 1,506,203.34
5. Step 5: Solve for x
   x = 1,506,203.34/1,380.23
6. Step 6: Final answer
   x = 1,091.27