Finding the Fourth Proportional to 21,011.52, 31,514.76 and 5,428.56

Step by Step Solution

1. Step 1: Write the proportion equation
   21,011.52 : 31,514.76 = 5,428.56 : x
2. Step 2: Convert to fraction form
   21,011.52/31,514.76 = 5,428.56/x
3. Step 3: Cross multiply
   21,011.52x = 31,514.76 × 5,428.56
4. Step 4: Simplify right side
   21,011.52x = 171,079,765.55
5. Step 5: Solve for x
   x = 171,079,765.55/21,011.52
6. Step 6: Final answer
   x = 8,142.19