Finding the Fourth Proportional to 1,216.57, 1,678.15 and 824.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,216.57 : 1,678.15 = 824.12 : x
2. Step 2: Convert to fraction form
   1,216.57/1,678.15 = 824.12/x
3. Step 3: Cross multiply
   1,216.57x = 1,678.15 × 824.12
4. Step 4: Simplify right side
   1,216.57x = 1,382,996.98
5. Step 5: Solve for x
   x = 1,382,996.98/1,216.57
6. Step 6: Final answer
   x = 1,136.80