Finding the Fourth Proportional to 1,275.78, 1,914.72 and 659.68

Step by Step Solution

1. Step 1: Write the proportion equation
   1,275.78 : 1,914.72 = 659.68 : x
2. Step 2: Convert to fraction form
   1,275.78/1,914.72 = 659.68/x
3. Step 3: Cross multiply
   1,275.78x = 1,914.72 × 659.68
4. Step 4: Simplify right side
   1,275.78x = 1,263,098.94
5. Step 5: Solve for x
   x = 1,263,098.94/1,275.78
6. Step 6: Final answer
   x = 990.06