Finding the Third Proportional to 78.40 and 104.77

Step by Step Solution

1. Step 1: Write the proportion equation
   78.40 : 104.77 = 104.77 : x
2. Step 2: Convert to fraction form
   78.40/104.77 = 104.77/x
3. Step 3: Cross multiply
   78.40x = 104.77 × 104.77
4. Step 4: Simplify right side
   78.40x = 10,975.84
5. Step 5: Solve for x
   x = 10,975.84/78.40
6. Step 6: Final answer
   x = 140.00