Finding the Fourth Proportional to 20,870.42, 31,317.92 and 7,731.95

Step by Step Solution

1. Step 1: Write the proportion equation
   20,870.42 : 31,317.92 = 7,731.95 : x
2. Step 2: Convert to fraction form
   20,870.42/31,317.92 = 7,731.95/x
3. Step 3: Cross multiply
   20,870.42x = 31,317.92 × 7,731.95
4. Step 4: Simplify right side
   20,870.42x = 242,148,552.88
5. Step 5: Solve for x
   x = 242,148,552.88/20,870.42
6. Step 6: Final answer
   x = 11,602.48