Finding the Fourth Proportional to 2,100.50, 3,154.35 and 1,991.06

Step by Step Solution

1. Step 1: Write the proportion equation
   2,100.50 : 3,154.35 = 1,991.06 : x
2. Step 2: Convert to fraction form
   2,100.50/3,154.35 = 1,991.06/x
3. Step 3: Cross multiply
   2,100.50x = 3,154.35 × 1,991.06
4. Step 4: Simplify right side
   2,100.50x = 6,280,500.11
5. Step 5: Solve for x
   x = 6,280,500.11/2,100.50
6. Step 6: Final answer
   x = 2,990.00