Finding the Fourth Proportional to 13,321.61, 19,980.52 and 5,427.57

Step by Step Solution

1. Step 1: Write the proportion equation
   13,321.61 : 19,980.52 = 5,427.57 : x
2. Step 2: Convert to fraction form
   13,321.61/19,980.52 = 5,427.57/x
3. Step 3: Cross multiply
   13,321.61x = 19,980.52 × 5,427.57
4. Step 4: Simplify right side
   13,321.61x = 108,445,670.94
5. Step 5: Solve for x
   x = 108,445,670.94/13,321.61
6. Step 6: Final answer
   x = 8,140.58