Finding the Fourth Proportional to 38,128.89, 52,619.82 and 21,990.21

Step by Step Solution

1. Step 1: Write the proportion equation
   38,128.89 : 52,619.82 = 21,990.21 : x
2. Step 2: Convert to fraction form
   38,128.89/52,619.82 = 21,990.21/x
3. Step 3: Cross multiply
   38,128.89x = 52,619.82 × 21,990.21
4. Step 4: Simplify right side
   38,128.89x = 1,157,120,612.17
5. Step 5: Solve for x
   x = 1,157,120,612.17/38,128.89
6. Step 6: Final answer
   x = 30,347.61