Finding the Fourth Proportional to 2,645.12, 3,962.78 and 1,912.88

Step by Step Solution

1. Step 1: Write the proportion equation
   2,645.12 : 3,962.78 = 1,912.88 : x
2. Step 2: Convert to fraction form
   2,645.12/3,962.78 = 1,912.88/x
3. Step 3: Cross multiply
   2,645.12x = 3,962.78 × 1,912.88
4. Step 4: Simplify right side
   2,645.12x = 7,580,322.61
5. Step 5: Solve for x
   x = 7,580,322.61/2,645.12
6. Step 6: Final answer
   x = 2,865.78