Finding the Third Proportional to 128.50 and 156.75

Step by Step Solution

1. Step 1: Write the proportion equation
   128.50 : 156.75 = 156.75 : x
2. Step 2: Convert to fraction form
   128.50/156.75 = 156.75/x
3. Step 3: Cross multiply
   128.50x = 156.75 × 156.75
4. Step 4: Simplify right side
   128.50x = 24,570.56
5. Step 5: Solve for x
   x = 24,570.56/128.50
6. Step 6: Final answer
   x = 191.21