Finding the Third Proportional to 128 and 191.50

Step by Step Solution

1. Step 1: Write the proportion equation
   128 : 191.50 = 191.50 : x
2. Step 2: Convert to fraction form
   128/191.50 = 191.50/x
3. Step 3: Cross multiply
   128x = 191.50 × 191.50
4. Step 4: Simplify right side
   128x = 36,672.25
5. Step 5: Solve for x
   x = 36,672.25/128
6. Step 6: Final answer
   x = 286.50