Finding the Fourth Proportional to 1,345.18, 2,019.48 and 823.90

Step by Step Solution

1. Step 1: Write the proportion equation
   1,345.18 : 2,019.48 = 823.90 : x
2. Step 2: Convert to fraction form
   1,345.18/2,019.48 = 823.90/x
3. Step 3: Cross multiply
   1,345.18x = 2,019.48 × 823.90
4. Step 4: Simplify right side
   1,345.18x = 1,663,849.57
5. Step 5: Solve for x
   x = 1,663,849.57/1,345.18
6. Step 6: Final answer
   x = 1,236.90