Finding the Fourth Proportional to 21,016.63, 31,521.64 and 5,815.61

Step by Step Solution

1. Step 1: Write the proportion equation
   21,016.63 : 31,521.64 = 5,815.61 : x
2. Step 2: Convert to fraction form
   21,016.63/31,521.64 = 5,815.61/x
3. Step 3: Cross multiply
   21,016.63x = 31,521.64 × 5,815.61
4. Step 4: Simplify right side
   21,016.63x = 183,317,564.80
5. Step 5: Solve for x
   x = 183,317,564.80/21,016.63
6. Step 6: Final answer
   x = 8,722.50