Finding the Fourth Proportional to 2,085.81, 3,129.13 and 931.56

Step by Step Solution

1. Step 1: Write the proportion equation
   2,085.81 : 3,129.13 = 931.56 : x
2. Step 2: Convert to fraction form
   2,085.81/3,129.13 = 931.56/x
3. Step 3: Cross multiply
   2,085.81x = 3,129.13 × 931.56
4. Step 4: Simplify right side
   2,085.81x = 2,914,972.34
5. Step 5: Solve for x
   x = 2,914,972.34/2,085.81
6. Step 6: Final answer
   x = 1,397.53