Finding the Fourth Proportional to 13,436, 18,538.72 and 7,770.72

Step by Step Solution

1. Step 1: Write the proportion equation
   13,436 : 18,538.72 = 7,770.72 : x
2. Step 2: Convert to fraction form
   13,436/18,538.72 = 7,770.72/x
3. Step 3: Cross multiply
   13,436x = 18,538.72 × 7,770.72
4. Step 4: Simplify right side
   13,436x = 144,059,202.28
5. Step 5: Solve for x
   x = 144,059,202.28/13,436
6. Step 6: Final answer
   x = 10,721.88