Finding the Third Proportional to 99,905 and 208,990

Step by Step Solution

1. Step 1: Write the proportion equation
   99,905 : 208,990 = 208,990 : x
2. Step 2: Convert to fraction form
   99,905/208,990 = 208,990/x
3. Step 3: Cross multiply
   99,905x = 208,990 × 208,990
4. Step 4: Simplify right side
   99,905x = 43,676,820,100
5. Step 5: Solve for x
   x = 43,676,820,100/99,905
6. Step 6: Final answer
   x = 437,183.53