Finding the Fourth Proportional to 2,085.13, 3,128.91 and 786.70

Step by Step Solution

1. Step 1: Write the proportion equation
   2,085.13 : 3,128.91 = 786.70 : x
2. Step 2: Convert to fraction form
   2,085.13/3,128.91 = 786.70/x
3. Step 3: Cross multiply
   2,085.13x = 3,128.91 × 786.70
4. Step 4: Simplify right side
   2,085.13x = 2,461,513.50
5. Step 5: Solve for x
   x = 2,461,513.50/2,085.13
6. Step 6: Final answer
   x = 1,180.51