Finding the Fourth Proportional to 1,380.51, 1,904.62 and 782.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,380.51 : 1,904.62 = 782.91 : x
2. Step 2: Convert to fraction form
   1,380.51/1,904.62 = 782.91/x
3. Step 3: Cross multiply
   1,380.51x = 1,904.62 × 782.91
4. Step 4: Simplify right side
   1,380.51x = 1,491,151.23
5. Step 5: Solve for x
   x = 1,491,151.23/1,380.51
6. Step 6: Final answer
   x = 1,080.15