Finding the Fourth Proportional to 30,890.75, 42,633.79 and 19,561.28

Step by Step Solution

1. Step 1: Write the proportion equation
   30,890.75 : 42,633.79 = 19,561.28 : x
2. Step 2: Convert to fraction form
   30,890.75/42,633.79 = 19,561.28/x
3. Step 3: Cross multiply
   30,890.75x = 42,633.79 × 19,561.28
4. Step 4: Simplify right side
   30,890.75x = 833,971,561.33
5. Step 5: Solve for x
   x = 833,971,561.33/30,890.75
6. Step 6: Final answer
   x = 26,997.45