Finding the Third Proportional to 99.56 and 218.81

Step by Step Solution

1. Step 1: Write the proportion equation
   99.56 : 218.81 = 218.81 : x
2. Step 2: Convert to fraction form
   99.56/218.81 = 218.81/x
3. Step 3: Cross multiply
   99.56x = 218.81 × 218.81
4. Step 4: Simplify right side
   99.56x = 47,878.91
5. Step 5: Solve for x
   x = 47,878.91/99.56
6. Step 6: Final answer
   x = 480.89