Finding the Third Proportional to 99,879 and 216,390

Step by Step Solution

1. Step 1: Write the proportion equation
   99,879 : 216,390 = 216,390 : x
2. Step 2: Convert to fraction form
   99,879/216,390 = 216,390/x
3. Step 3: Cross multiply
   99,879x = 216,390 × 216,390
4. Step 4: Simplify right side
   99,879x = 46,824,632,100
5. Step 5: Solve for x
   x = 46,824,632,100/99,879
6. Step 6: Final answer
   x = 468,813.59