Finding the Fourth Proportional to 2,086.63, 3,128.73 and 788.20

Step by Step Solution

1. Step 1: Write the proportion equation
   2,086.63 : 3,128.73 = 788.20 : x
2. Step 2: Convert to fraction form
   2,086.63/3,128.73 = 788.20/x
3. Step 3: Cross multiply
   2,086.63x = 3,128.73 × 788.20
4. Step 4: Simplify right side
   2,086.63x = 2,466,064.99
5. Step 5: Solve for x
   x = 2,466,064.99/2,086.63
6. Step 6: Final answer
   x = 1,181.84