Finding the Fourth Proportional to 2,631.34, 3,947.39 and 875.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,631.34 : 3,947.39 = 875.78 : x
2. Step 2: Convert to fraction form
   2,631.34/3,947.39 = 875.78/x
3. Step 3: Cross multiply
   2,631.34x = 3,947.39 × 875.78
4. Step 4: Simplify right side
   2,631.34x = 3,457,045.21
5. Step 5: Solve for x
   x = 3,457,045.21/2,631.34
6. Step 6: Final answer
   x = 1,313.80