Finding the Third Proportional to 660,144 and 991,680

Step by Step Solution

1. Step 1: Write the proportion equation
   660,144 : 991,680 = 991,680 : x
2. Step 2: Convert to fraction form
   660,144/991,680 = 991,680/x
3. Step 3: Cross multiply
   660,144x = 991,680 × 991,680
4. Step 4: Simplify right side
   660,144x = 983,429,222,400
5. Step 5: Solve for x
   x = 983,429,222,400/660,144
6. Step 6: Final answer
   x = 1,489,719.25