Finding the Third Proportional to 131.91 and 218.81

Step by Step Solution

1. Step 1: Write the proportion equation
   131.91 : 218.81 = 218.81 : x
2. Step 2: Convert to fraction form
   131.91/218.81 = 218.81/x
3. Step 3: Cross multiply
   131.91x = 218.81 × 218.81
4. Step 4: Simplify right side
   131.91x = 47,878.91
5. Step 5: Solve for x
   x = 47,878.91/131.91
6. Step 6: Final answer
   x = 362.98