Finding the Fourth Proportional to 2,109.90, 3,163.20 and 1,288.02

Step by Step Solution

1. Step 1: Write the proportion equation
   2,109.90 : 3,163.20 = 1,288.02 : x
2. Step 2: Convert to fraction form
   2,109.90/3,163.20 = 1,288.02/x
3. Step 3: Cross multiply
   2,109.90x = 3,163.20 × 1,288.02
4. Step 4: Simplify right side
   2,109.90x = 4,074,264.86
5. Step 5: Solve for x
   x = 4,074,264.86/2,109.90
6. Step 6: Final answer
   x = 1,931.02