Finding the Fourth Proportional to 53,123.12, 79,684.74 and 13,680.32

Step by Step Solution

1. Step 1: Write the proportion equation
   53,123.12 : 79,684.74 = 13,680.32 : x
2. Step 2: Convert to fraction form
   53,123.12/79,684.74 = 13,680.32/x
3. Step 3: Cross multiply
   53,123.12x = 79,684.74 × 13,680.32
4. Step 4: Simplify right side
   53,123.12x = 1,090,112,742.32
5. Step 5: Solve for x
   x = 1,090,112,742.32/53,123.12
6. Step 6: Final answer
   x = 20,520.50