Finding the Third Proportional to 128.50 and 222.13

Step by Step Solution

1. Step 1: Write the proportion equation
   128.50 : 222.13 = 222.13 : x
2. Step 2: Convert to fraction form
   128.50/222.13 = 222.13/x
3. Step 3: Cross multiply
   128.50x = 222.13 × 222.13
4. Step 4: Simplify right side
   128.50x = 49,339.52
5. Step 5: Solve for x
   x = 49,339.52/128.50
6. Step 6: Final answer
   x = 383.97