Finding the Fourth Proportional to 1,856.72, 2,782.35 and 815.77

Step by Step Solution

1. Step 1: Write the proportion equation
   1,856.72 : 2,782.35 = 815.77 : x
2. Step 2: Convert to fraction form
   1,856.72/2,782.35 = 815.77/x
3. Step 3: Cross multiply
   1,856.72x = 2,782.35 × 815.77
4. Step 4: Simplify right side
   1,856.72x = 2,269,761.14
5. Step 5: Solve for x
   x = 2,269,761.14/1,856.72
6. Step 6: Final answer
   x = 1,222.46