Finding the Third Proportional to 51,120 and 78,960

Step by Step Solution

1. Step 1: Write the proportion equation
   51,120 : 78,960 = 78,960 : x
2. Step 2: Convert to fraction form
   51,120/78,960 = 78,960/x
3. Step 3: Cross multiply
   51,120x = 78,960 × 78,960
4. Step 4: Simplify right side
   51,120x = 6,234,681,600
5. Step 5: Solve for x
   x = 6,234,681,600/51,120
6. Step 6: Final answer
   x = 121,961.69