Finding the Fourth Proportional to 1,535.15, 2,117.91 and 871.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,535.15 : 2,117.91 = 871.91 : x
2. Step 2: Convert to fraction form
   1,535.15/2,117.91 = 871.91/x
3. Step 3: Cross multiply
   1,535.15x = 2,117.91 × 871.91
4. Step 4: Simplify right side
   1,535.15x = 1,846,622.55
5. Step 5: Solve for x
   x = 1,846,622.55/1,535.15
6. Step 6: Final answer
   x = 1,202.90