Finding the Third Proportional to 128.50 and 347.50

Step by Step Solution

1. Step 1: Write the proportion equation
   128.50 : 347.50 = 347.50 : x
2. Step 2: Convert to fraction form
   128.50/347.50 = 347.50/x
3. Step 3: Cross multiply
   128.50x = 347.50 × 347.50
4. Step 4: Simplify right side
   128.50x = 120,756.25
5. Step 5: Solve for x
   x = 120,756.25/128.50
6. Step 6: Final answer
   x = 939.74