Finding the Fourth Proportional to 22,926, 31,638.84 and 12,990

Step by Step Solution

1. Step 1: Write the proportion equation
   22,926 : 31,638.84 = 12,990 : x
2. Step 2: Convert to fraction form
   22,926/31,638.84 = 12,990/x
3. Step 3: Cross multiply
   22,926x = 31,638.84 × 12,990
4. Step 4: Simplify right side
   22,926x = 410,988,531.60
5. Step 5: Solve for x
   x = 410,988,531.60/22,926
6. Step 6: Final answer
   x = 17,926.74