Finding the Fourth Proportional to 1,016.76, 1,401.60 and 780.84

Step by Step Solution

1. Step 1: Write the proportion equation
   1,016.76 : 1,401.60 = 780.84 : x
2. Step 2: Convert to fraction form
   1,016.76/1,401.60 = 780.84/x
3. Step 3: Cross multiply
   1,016.76x = 1,401.60 × 780.84
4. Step 4: Simplify right side
   1,016.76x = 1,094,425.34
5. Step 5: Solve for x
   x = 1,094,425.34/1,016.76
6. Step 6: Final answer
   x = 1,076.39