Finding the Third Proportional to 99,911 and 215,815.50

Step by Step Solution

1. Step 1: Write the proportion equation
   99,911 : 215,815.50 = 215,815.50 : x
2. Step 2: Convert to fraction form
   99,911/215,815.50 = 215,815.50/x
3. Step 3: Cross multiply
   99,911x = 215,815.50 × 215,815.50
4. Step 4: Simplify right side
   99,911x = 46,576,330,040.25
5. Step 5: Solve for x
   x = 46,576,330,040.25/99,911
6. Step 6: Final answer
   x = 466,178.20