Finding the Fourth Proportional to 1,407.60, 1,942.16 and 817.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,407.60 : 1,942.16 = 817.80 : x
2. Step 2: Convert to fraction form
   1,407.60/1,942.16 = 817.80/x
3. Step 3: Cross multiply
   1,407.60x = 1,942.16 × 817.80
4. Step 4: Simplify right side
   1,407.60x = 1,588,298.45
5. Step 5: Solve for x
   x = 1,588,298.45/1,407.60
6. Step 6: Final answer
   x = 1,128.37