Finding the Fourth Proportional to 21,238.50, 31,870.71 and 8,926.50

Step by Step Solution

1. Step 1: Write the proportion equation
   21,238.50 : 31,870.71 = 8,926.50 : x
2. Step 2: Convert to fraction form
   21,238.50/31,870.71 = 8,926.50/x
3. Step 3: Cross multiply
   21,238.50x = 31,870.71 × 8,926.50
4. Step 4: Simplify right side
   21,238.50x = 284,493,892.82
5. Step 5: Solve for x
   x = 284,493,892.82/21,238.50
6. Step 6: Final answer
   x = 13,395.20