Finding the Fourth Proportional to 2,085.31, 3,128.51 and 786.79

Step by Step Solution

1. Step 1: Write the proportion equation
   2,085.31 : 3,128.51 = 786.79 : x
2. Step 2: Convert to fraction form
   2,085.31/3,128.51 = 786.79/x
3. Step 3: Cross multiply
   2,085.31x = 3,128.51 × 786.79
4. Step 4: Simplify right side
   2,085.31x = 2,461,476.45
5. Step 5: Solve for x
   x = 2,461,476.45/2,085.31
6. Step 6: Final answer
   x = 1,180.39