Finding the Fourth Proportional to 13,780.56, 20,667.42 and 5,457.72

Step by Step Solution

1. Step 1: Write the proportion equation
   13,780.56 : 20,667.42 = 5,457.72 : x
2. Step 2: Convert to fraction form
   13,780.56/20,667.42 = 5,457.72/x
3. Step 3: Cross multiply
   13,780.56x = 20,667.42 × 5,457.72
4. Step 4: Simplify right side
   13,780.56x = 112,796,991.48
5. Step 5: Solve for x
   x = 112,796,991.48/13,780.56
6. Step 6: Final answer
   x = 8,185.23