Finding the Fourth Proportional to 21,079.38, 31,631.72 and 8,426.87

Step by Step Solution

1. Step 1: Write the proportion equation
   21,079.38 : 31,631.72 = 8,426.87 : x
2. Step 2: Convert to fraction form
   21,079.38/31,631.72 = 8,426.87/x
3. Step 3: Cross multiply
   21,079.38x = 31,631.72 × 8,426.87
4. Step 4: Simplify right side
   21,079.38x = 266,556,392.32
5. Step 5: Solve for x
   x = 266,556,392.32/21,079.38
6. Step 6: Final answer
   x = 12,645.36