Finding the Fourth Proportional to 1,821.15, 2,512.28 and 1,223.98

Step by Step Solution

1. Step 1: Write the proportion equation
   1,821.15 : 2,512.28 = 1,223.98 : x
2. Step 2: Convert to fraction form
   1,821.15/2,512.28 = 1,223.98/x
3. Step 3: Cross multiply
   1,821.15x = 2,512.28 × 1,223.98
4. Step 4: Simplify right side
   1,821.15x = 3,074,977.25
5. Step 5: Solve for x
   x = 3,074,977.25/1,821.15
6. Step 6: Final answer
   x = 1,688.48