Finding the Third Proportional to 209,991 and 316,066.50

Step by Step Solution

1. Step 1: Write the proportion equation
   209,991 : 316,066.50 = 316,066.50 : x
2. Step 2: Convert to fraction form
   209,991/316,066.50 = 316,066.50/x
3. Step 3: Cross multiply
   209,991x = 316,066.50 × 316,066.50
4. Step 4: Simplify right side
   209,991x = 99,898,032,422.25
5. Step 5: Solve for x
   x = 99,898,032,422.25/209,991
6. Step 6: Final answer
   x = 475,725.30