Finding the Fourth Proportional to 3,886.90, 5,363.91 and 2,118.50

Step by Step Solution

1. Step 1: Write the proportion equation
   3,886.90 : 5,363.91 = 2,118.50 : x
2. Step 2: Convert to fraction form
   3,886.90/5,363.91 = 2,118.50/x
3. Step 3: Cross multiply
   3,886.90x = 5,363.91 × 2,118.50
4. Step 4: Simplify right side
   3,886.90x = 11,363,416.52
5. Step 5: Solve for x
   x = 11,363,416.52/3,886.90
6. Step 6: Final answer
   x = 2,923.52