Finding the Fourth Proportional to 2,990.87, 4,128.86 and 1,872.43

Step by Step Solution

1. Step 1: Write the proportion equation
   2,990.87 : 4,128.86 = 1,872.43 : x
2. Step 2: Convert to fraction form
   2,990.87/4,128.86 = 1,872.43/x
3. Step 3: Cross multiply
   2,990.87x = 4,128.86 × 1,872.43
4. Step 4: Simplify right side
   2,990.87x = 7,730,995.69
5. Step 5: Solve for x
   x = 7,730,995.69/2,990.87
6. Step 6: Final answer
   x = 2,584.87