Finding the Fourth Proportional to 13,611.72, 18,783.15 and 7,642.25

Step by Step Solution

1. Step 1: Write the proportion equation
   13,611.72 : 18,783.15 = 7,642.25 : x
2. Step 2: Convert to fraction form
   13,611.72/18,783.15 = 7,642.25/x
3. Step 3: Cross multiply
   13,611.72x = 18,783.15 × 7,642.25
4. Step 4: Simplify right side
   13,611.72x = 143,545,434.17
5. Step 5: Solve for x
   x = 143,545,434.17/13,611.72
6. Step 6: Final answer
   x = 10,545.72