Finding the Third Proportional to 191,760 and 287,640

Step by Step Solution

1. Step 1: Write the proportion equation
   191,760 : 287,640 = 287,640 : x
2. Step 2: Convert to fraction form
   191,760/287,640 = 287,640/x
3. Step 3: Cross multiply
   191,760x = 287,640 × 287,640
4. Step 4: Simplify right side
   191,760x = 82,736,769,600
5. Step 5: Solve for x
   x = 82,736,769,600/191,760
6. Step 6: Final answer
   x = 431,460