Finding the Fourth Proportional to 1,012.77, 1,516.71 and 578.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,012.77 : 1,516.71 = 578.61 : x
2. Step 2: Convert to fraction form
   1,012.77/1,516.71 = 578.61/x
3. Step 3: Cross multiply
   1,012.77x = 1,516.71 × 578.61
4. Step 4: Simplify right side
   1,012.77x = 877,583.57
5. Step 5: Solve for x
   x = 877,583.57/1,012.77
6. Step 6: Final answer
   x = 866.52