Finding the Fourth Proportional to 15,494.34, 21,381.30 and 8,420.71

Step by Step Solution

1. Step 1: Write the proportion equation
   15,494.34 : 21,381.30 = 8,420.71 : x
2. Step 2: Convert to fraction form
   15,494.34/21,381.30 = 8,420.71/x
3. Step 3: Cross multiply
   15,494.34x = 21,381.30 × 8,420.71
4. Step 4: Simplify right side
   15,494.34x = 180,045,619.82
5. Step 5: Solve for x
   x = 180,045,619.82/15,494.34
6. Step 6: Final answer
   x = 11,620.09