Finding the Fourth Proportional to 21,055.91, 31,556.48 and 8,561.37

Step by Step Solution

1. Step 1: Write the proportion equation
   21,055.91 : 31,556.48 = 8,561.37 : x
2. Step 2: Convert to fraction form
   21,055.91/31,556.48 = 8,561.37/x
3. Step 3: Cross multiply
   21,055.91x = 31,556.48 × 8,561.37
4. Step 4: Simplify right side
   21,055.91x = 270,166,658.37
5. Step 5: Solve for x
   x = 270,166,658.37/21,055.91
6. Step 6: Final answer
   x = 12,830.92