Finding the Fourth Proportional to 91,509.21, 136,654.83 and 90,519.59

Step by Step Solution

1. Step 1: Write the proportion equation
   91,509.21 : 136,654.83 = 90,519.59 : x
2. Step 2: Convert to fraction form
   91,509.21/136,654.83 = 90,519.59/x
3. Step 3: Cross multiply
   91,509.21x = 136,654.83 × 90,519.59
4. Step 4: Simplify right side
   91,509.21x = 12,369,939,524.76
5. Step 5: Solve for x
   x = 12,369,939,524.76/91,509.21
6. Step 6: Final answer
   x = 135,176.99