Finding the Fourth Proportional to 13,608.87, 18,780.15 and 7,640.52

Step by Step Solution

1. Step 1: Write the proportion equation
   13,608.87 : 18,780.15 = 7,640.52 : x
2. Step 2: Convert to fraction form
   13,608.87/18,780.15 = 7,640.52/x
3. Step 3: Cross multiply
   13,608.87x = 18,780.15 × 7,640.52
4. Step 4: Simplify right side
   13,608.87x = 143,490,111.68
5. Step 5: Solve for x
   x = 143,490,111.68/13,608.87
6. Step 6: Final answer
   x = 10,543.87