Finding the Fourth Proportional to 15,739.89, 21,722.28 and 8,667.57

Step by Step Solution

1. Step 1: Write the proportion equation
   15,739.89 : 21,722.28 = 8,667.57 : x
2. Step 2: Convert to fraction form
   15,739.89/21,722.28 = 8,667.57/x
3. Step 3: Cross multiply
   15,739.89x = 21,722.28 × 8,667.57
4. Step 4: Simplify right side
   15,739.89x = 188,279,382.46
5. Step 5: Solve for x
   x = 188,279,382.46/15,739.89
6. Step 6: Final answer
   x = 11,961.92