Finding the Third Proportional to 99.70 and 208.50

Step by Step Solution

1. Step 1: Write the proportion equation
   99.70 : 208.50 = 208.50 : x
2. Step 2: Convert to fraction form
   99.70/208.50 = 208.50/x
3. Step 3: Cross multiply
   99.70x = 208.50 × 208.50
4. Step 4: Simplify right side
   99.70x = 43,472.25
5. Step 5: Solve for x
   x = 43,472.25/99.70
6. Step 6: Final answer
   x = 436.02