Finding the Fourth Proportional to 3,779.28, 5,215.50 and 2,100.78

Step by Step Solution

1. Step 1: Write the proportion equation
   3,779.28 : 5,215.50 = 2,100.78 : x
2. Step 2: Convert to fraction form
   3,779.28/5,215.50 = 2,100.78/x
3. Step 3: Cross multiply
   3,779.28x = 5,215.50 × 2,100.78
4. Step 4: Simplify right side
   3,779.28x = 10,956,618.09
5. Step 5: Solve for x
   x = 10,956,618.09/3,779.28
6. Step 6: Final answer
   x = 2,899.13