Finding the Third Proportional to 78.75 and 122.25

Step by Step Solution

1. Step 1: Write the proportion equation
   78.75 : 122.25 = 122.25 : x
2. Step 2: Convert to fraction form
   78.75/122.25 = 122.25/x
3. Step 3: Cross multiply
   78.75x = 122.25 × 122.25
4. Step 4: Simplify right side
   78.75x = 14,945.06
5. Step 5: Solve for x
   x = 14,945.06/78.75
6. Step 6: Final answer
   x = 189.78