Finding the Fourth Proportional to 1,081.50, 1,492.50 and 615.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.50 : 1,492.50 = 615.78 : x
2. Step 2: Convert to fraction form
   1,081.50/1,492.50 = 615.78/x
3. Step 3: Cross multiply
   1,081.50x = 1,492.50 × 615.78
4. Step 4: Simplify right side
   1,081.50x = 919,051.65
5. Step 5: Solve for x
   x = 919,051.65/1,081.50
6. Step 6: Final answer
   x = 849.79