Finding the Fourth Proportional to 1,315.76, 1,815.12 and 868.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,315.76 : 1,815.12 = 868.10 : x
2. Step 2: Convert to fraction form
   1,315.76/1,815.12 = 868.10/x
3. Step 3: Cross multiply
   1,315.76x = 1,815.12 × 868.10
4. Step 4: Simplify right side
   1,315.76x = 1,575,696.60
5. Step 5: Solve for x
   x = 1,575,696.60/1,315.76
6. Step 6: Final answer
   x = 1,197.56