Finding the Third Proportional to 199.89 and 431.42

Step by Step Solution

1. Step 1: Write the proportion equation
   199.89 : 431.42 = 431.42 : x
2. Step 2: Convert to fraction form
   199.89/431.42 = 431.42/x
3. Step 3: Cross multiply
   199.89x = 431.42 × 431.42
4. Step 4: Simplify right side
   199.89x = 186,123.15
5. Step 5: Solve for x
   x = 186,123.15/199.89
6. Step 6: Final answer
   x = 931.13