Finding the Third Proportional to 200,128 and 309,543.50

Step by Step Solution

1. Step 1: Write the proportion equation
   200,128 : 309,543.50 = 309,543.50 : x
2. Step 2: Convert to fraction form
   200,128/309,543.50 = 309,543.50/x
3. Step 3: Cross multiply
   200,128x = 309,543.50 × 309,543.50
4. Step 4: Simplify right side
   200,128x = 95,817,178,392.25
5. Step 5: Solve for x
   x = 95,817,178,392.25/200,128
6. Step 6: Final answer
   x = 478,779.47