Finding the Fourth Proportional to 99,021, 136,656.18 and 56,578.62

Step by Step Solution

1. Step 1: Write the proportion equation
   99,021 : 136,656.18 = 56,578.62 : x
2. Step 2: Convert to fraction form
   99,021/136,656.18 = 56,578.62/x
3. Step 3: Cross multiply
   99,021x = 136,656.18 × 56,578.62
4. Step 4: Simplify right side
   99,021x = 7,731,818,078.87
5. Step 5: Solve for x
   x = 7,731,818,078.87/99,021
6. Step 6: Final answer
   x = 78,082.61