Finding the Third Proportional to 78.75 and 115.50

Step by Step Solution

1. Step 1: Write the proportion equation
   78.75 : 115.50 = 115.50 : x
2. Step 2: Convert to fraction form
   78.75/115.50 = 115.50/x
3. Step 3: Cross multiply
   78.75x = 115.50 × 115.50
4. Step 4: Simplify right side
   78.75x = 13,340.25
5. Step 5: Solve for x
   x = 13,340.25/78.75
6. Step 6: Final answer
   x = 169.40