Finding the Fourth Proportional to 1,906.72, 2,858.40 and 810.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,906.72 : 2,858.40 = 810.88 : x
2. Step 2: Convert to fraction form
   1,906.72/2,858.40 = 810.88/x
3. Step 3: Cross multiply
   1,906.72x = 2,858.40 × 810.88
4. Step 4: Simplify right side
   1,906.72x = 2,317,819.39
5. Step 5: Solve for x
   x = 2,317,819.39/1,906.72
6. Step 6: Final answer
   x = 1,215.61