Finding the Fourth Proportional to 20,705.58, 31,057.98 and 5,123.20

Step by Step Solution

1. Step 1: Write the proportion equation
   20,705.58 : 31,057.98 = 5,123.20 : x
2. Step 2: Convert to fraction form
   20,705.58/31,057.98 = 5,123.20/x
3. Step 3: Cross multiply
   20,705.58x = 31,057.98 × 5,123.20
4. Step 4: Simplify right side
   20,705.58x = 159,116,243.14
5. Step 5: Solve for x
   x = 159,116,243.14/20,705.58
6. Step 6: Final answer
   x = 7,684.70