Finding the Fourth Proportional to 2,990.78, 4,479.21 and 2,886.96

Step by Step Solution

1. Step 1: Write the proportion equation
   2,990.78 : 4,479.21 = 2,886.96 : x
2. Step 2: Convert to fraction form
   2,990.78/4,479.21 = 2,886.96/x
3. Step 3: Cross multiply
   2,990.78x = 4,479.21 × 2,886.96
4. Step 4: Simplify right side
   2,990.78x = 12,931,300.10
5. Step 5: Solve for x
   x = 12,931,300.10/2,990.78
6. Step 6: Final answer
   x = 4,323.72