Finding the Fourth Proportional to 1,278.78, 1,764.72 and 719.25

Step by Step Solution

1. Step 1: Write the proportion equation
   1,278.78 : 1,764.72 = 719.25 : x
2. Step 2: Convert to fraction form
   1,278.78/1,764.72 = 719.25/x
3. Step 3: Cross multiply
   1,278.78x = 1,764.72 × 719.25
4. Step 4: Simplify right side
   1,278.78x = 1,269,274.86
5. Step 5: Solve for x
   x = 1,269,274.86/1,278.78
6. Step 6: Final answer
   x = 992.57