Finding the Fourth Proportional to 2,086.92, 3,130.56 and 991.80

Step by Step Solution

1. Step 1: Write the proportion equation
   2,086.92 : 3,130.56 = 991.80 : x
2. Step 2: Convert to fraction form
   2,086.92/3,130.56 = 991.80/x
3. Step 3: Cross multiply
   2,086.92x = 3,130.56 × 991.80
4. Step 4: Simplify right side
   2,086.92x = 3,104,889.41
5. Step 5: Solve for x
   x = 3,104,889.41/2,086.92
6. Step 6: Final answer
   x = 1,487.79