Finding the Fourth Proportional to 1,275.11, 1,759.71 and 715.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,275.11 : 1,759.71 = 715.55 : x
2. Step 2: Convert to fraction form
   1,275.11/1,759.71 = 715.55/x
3. Step 3: Cross multiply
   1,275.11x = 1,759.71 × 715.55
4. Step 4: Simplify right side
   1,275.11x = 1,259,151.69
5. Step 5: Solve for x
   x = 1,259,151.69/1,275.11
6. Step 6: Final answer
   x = 987.49