Finding the Fourth Proportional to 2,102.56, 3,151.78 and 870.84

Step by Step Solution

1. Step 1: Write the proportion equation
   2,102.56 : 3,151.78 = 870.84 : x
2. Step 2: Convert to fraction form
   2,102.56/3,151.78 = 870.84/x
3. Step 3: Cross multiply
   2,102.56x = 3,151.78 × 870.84
4. Step 4: Simplify right side
   2,102.56x = 2,744,696.10
5. Step 5: Solve for x
   x = 2,744,696.10/2,102.56
6. Step 6: Final answer
   x = 1,305.41