Finding the Fourth Proportional to 1,665.60, 2,495.04 and 800.40

Step by Step Solution

1. Step 1: Write the proportion equation
   1,665.60 : 2,495.04 = 800.40 : x
2. Step 2: Convert to fraction form
   1,665.60/2,495.04 = 800.40/x
3. Step 3: Cross multiply
   1,665.60x = 2,495.04 × 800.40
4. Step 4: Simplify right side
   1,665.60x = 1,997,030.02
5. Step 5: Solve for x
   x = 1,997,030.02/1,665.60
6. Step 6: Final answer
   x = 1,198.99