Finding the Fourth Proportional to 21,018.82, 31,528.16 and 6,979.91

Step by Step Solution

1. Step 1: Write the proportion equation
   21,018.82 : 31,528.16 = 6,979.91 : x
2. Step 2: Convert to fraction form
   21,018.82/31,528.16 = 6,979.91/x
3. Step 3: Cross multiply
   21,018.82x = 31,528.16 × 6,979.91
4. Step 4: Simplify right side
   21,018.82x = 220,063,719.27
5. Step 5: Solve for x
   x = 220,063,719.27/21,018.82
6. Step 6: Final answer
   x = 10,469.84