Finding the Third Proportional to 1,139.63 and 1,369.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.63 : 1,369.69 = 1,369.69 : x
2. Step 2: Convert to fraction form
   1,139.63/1,369.69 = 1,369.69/x
3. Step 3: Cross multiply
   1,139.63x = 1,369.69 × 1,369.69
4. Step 4: Simplify right side
   1,139.63x = 1,876,043.85
5. Step 5: Solve for x
   x = 1,876,043.85/1,139.63
6. Step 6: Final answer
   x = 1,646.19