Finding the Fourth Proportional to 3,120.50, 4,680.42 and 812.00

Step by Step Solution

1. Step 1: Write the proportion equation
   3,120.50 : 4,680.42 = 812.00 : x
2. Step 2: Convert to fraction form
   3,120.50/4,680.42 = 812.00/x
3. Step 3: Cross multiply
   3,120.50x = 4,680.42 × 812.00
4. Step 4: Simplify right side
   3,120.50x = 3,800,477.64
5. Step 5: Solve for x
   x = 3,800,477.64/3,120.50
6. Step 6: Final answer
   x = 1,217.91