Finding the Fourth Proportional to 20,691.42, 31,037.31 and 5,109.18

Step by Step Solution

1. Step 1: Write the proportion equation
   20,691.42 : 31,037.31 = 5,109.18 : x
2. Step 2: Convert to fraction form
   20,691.42/31,037.31 = 5,109.18/x
3. Step 3: Cross multiply
   20,691.42x = 31,037.31 × 5,109.18
4. Step 4: Simplify right side
   20,691.42x = 158,575,203.51
5. Step 5: Solve for x
   x = 158,575,203.51/20,691.42
6. Step 6: Final answer
   x = 7,663.81