Finding the Fourth Proportional to 1,315.67, 1,815.61 and 718.16

Step by Step Solution

1. Step 1: Write the proportion equation
   1,315.67 : 1,815.61 = 718.16 : x
2. Step 2: Convert to fraction form
   1,315.67/1,815.61 = 718.16/x
3. Step 3: Cross multiply
   1,315.67x = 1,815.61 × 718.16
4. Step 4: Simplify right side
   1,315.67x = 1,303,887.60
5. Step 5: Solve for x
   x = 1,303,887.60/1,315.67
6. Step 6: Final answer
   x = 991.05