Finding the Fourth Proportional to 20,783.99, 31,185.12 and 10,920.98

Step by Step Solution

1. Step 1: Write the proportion equation
   20,783.99 : 31,185.12 = 10,920.98 : x
2. Step 2: Convert to fraction form
   20,783.99/31,185.12 = 10,920.98/x
3. Step 3: Cross multiply
   20,783.99x = 31,185.12 × 10,920.98
4. Step 4: Simplify right side
   20,783.99x = 340,572,071.82
5. Step 5: Solve for x
   x = 340,572,071.82/20,783.99
6. Step 6: Final answer
   x = 16,386.27