Finding the Fourth Proportional to 39,870.31, 55,019.73 and 21,965.26

Step by Step Solution

1. Step 1: Write the proportion equation
   39,870.31 : 55,019.73 = 21,965.26 : x
2. Step 2: Convert to fraction form
   39,870.31/55,019.73 = 21,965.26/x
3. Step 3: Cross multiply
   39,870.31x = 55,019.73 × 21,965.26
4. Step 4: Simplify right side
   39,870.31x = 1,208,522,674.58
5. Step 5: Solve for x
   x = 1,208,522,674.58/39,870.31
6. Step 6: Final answer
   x = 30,311.34