Finding the Fourth Proportional to 137,128.32, 205,779.96 and 91,638.72

Step by Step Solution

1. Step 1: Write the proportion equation
   137,128.32 : 205,779.96 = 91,638.72 : x
2. Step 2: Convert to fraction form
   137,128.32/205,779.96 = 91,638.72/x
3. Step 3: Cross multiply
   137,128.32x = 205,779.96 × 91,638.72
4. Step 4: Simplify right side
   137,128.32x = 18,857,412,136.05
5. Step 5: Solve for x
   x = 18,857,412,136.05/137,128.32
6. Step 6: Final answer
   x = 137,516.54