Finding the Third Proportional to 91.60 and 139.30

Step by Step Solution

1. Step 1: Write the proportion equation
   91.60 : 139.30 = 139.30 : x
2. Step 2: Convert to fraction form
   91.60/139.30 = 139.30/x
3. Step 3: Cross multiply
   91.60x = 139.30 × 139.30
4. Step 4: Simplify right side
   91.60x = 19,403.89
5. Step 5: Solve for x
   x = 19,403.89/91.60
6. Step 6: Final answer
   x = 211.83