Finding the Fourth Proportional to 1,316.52, 1,812.78 and 1,225.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,316.52 : 1,812.78 = 1,225.80 : x
2. Step 2: Convert to fraction form
   1,316.52/1,812.78 = 1,225.80/x
3. Step 3: Cross multiply
   1,316.52x = 1,812.78 × 1,225.80
4. Step 4: Simplify right side
   1,316.52x = 2,222,105.72
5. Step 5: Solve for x
   x = 2,222,105.72/1,316.52
6. Step 6: Final answer
   x = 1,687.86