Finding the Fourth Proportional to 1,407.40, 1,942.35 and 817.90

Step by Step Solution

1. Step 1: Write the proportion equation
   1,407.40 : 1,942.35 = 817.90 : x
2. Step 2: Convert to fraction form
   1,407.40/1,942.35 = 817.90/x
3. Step 3: Cross multiply
   1,407.40x = 1,942.35 × 817.90
4. Step 4: Simplify right side
   1,407.40x = 1,588,648.07
5. Step 5: Solve for x
   x = 1,588,648.07/1,407.40
6. Step 6: Final answer
   x = 1,128.78