Finding the Fourth Proportional to 2,631.78, 3,947.84 and 876.71

Step by Step Solution

1. Step 1: Write the proportion equation
   2,631.78 : 3,947.84 = 876.71 : x
2. Step 2: Convert to fraction form
   2,631.78/3,947.84 = 876.71/x
3. Step 3: Cross multiply
   2,631.78x = 3,947.84 × 876.71
4. Step 4: Simplify right side
   2,631.78x = 3,461,110.81
5. Step 5: Solve for x
   x = 3,461,110.81/2,631.78
6. Step 6: Final answer
   x = 1,315.12