Finding the Fourth Proportional to 13,721.76, 18,936.18 and 7,434.15

Step by Step Solution

1. Step 1: Write the proportion equation
   13,721.76 : 18,936.18 = 7,434.15 : x
2. Step 2: Convert to fraction form
   13,721.76/18,936.18 = 7,434.15/x
3. Step 3: Cross multiply
   13,721.76x = 18,936.18 × 7,434.15
4. Step 4: Simplify right side
   13,721.76x = 140,774,402.55
5. Step 5: Solve for x
   x = 140,774,402.55/13,721.76
6. Step 6: Final answer
   x = 10,259.21