Finding the Third Proportional to 87,790.50 and 128,830.50

Step by Step Solution

1. Step 1: Write the proportion equation
   87,790.50 : 128,830.50 = 128,830.50 : x
2. Step 2: Convert to fraction form
   87,790.50/128,830.50 = 128,830.50/x
3. Step 3: Cross multiply
   87,790.50x = 128,830.50 × 128,830.50
4. Step 4: Simplify right side
   87,790.50x = 16,597,297,730.25
5. Step 5: Solve for x
   x = 16,597,297,730.25/87,790.50
6. Step 6: Final answer
   x = 189,055.74