Finding the Fourth Proportional to 1,081.60, 1,492.64 and 661.92

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.60 : 1,492.64 = 661.92 : x
2. Step 2: Convert to fraction form
   1,081.60/1,492.64 = 661.92/x
3. Step 3: Cross multiply
   1,081.60x = 1,492.64 × 661.92
4. Step 4: Simplify right side
   1,081.60x = 988,008.27
5. Step 5: Solve for x
   x = 988,008.27/1,081.60
6. Step 6: Final answer
   x = 913.47