Finding the Fourth Proportional to 2,085.90, 3,128.73 and 525.88

Step by Step Solution

1. Step 1: Write the proportion equation
   2,085.90 : 3,128.73 = 525.88 : x
2. Step 2: Convert to fraction form
   2,085.90/3,128.73 = 525.88/x
3. Step 3: Cross multiply
   2,085.90x = 3,128.73 × 525.88
4. Step 4: Simplify right side
   2,085.90x = 1,645,336.53
5. Step 5: Solve for x
   x = 1,645,336.53/2,085.90
6. Step 6: Final answer
   x = 788.79