Finding the Third Proportional to 99.19 and 217.31

Step by Step Solution

1. Step 1: Write the proportion equation
   99.19 : 217.31 = 217.31 : x
2. Step 2: Convert to fraction form
   99.19/217.31 = 217.31/x
3. Step 3: Cross multiply
   99.19x = 217.31 × 217.31
4. Step 4: Simplify right side
   99.19x = 47,224.72
5. Step 5: Solve for x
   x = 47,224.72/99.19
6. Step 6: Final answer
   x = 476.12