Finding the Third Proportional to 1,288.69 and 2,130.47

Step by Step Solution

1. Step 1: Write the proportion equation
   1,288.69 : 2,130.47 = 2,130.47 : x
2. Step 2: Convert to fraction form
   1,288.69/2,130.47 = 2,130.47/x
3. Step 3: Cross multiply
   1,288.69x = 2,130.47 × 2,130.47
4. Step 4: Simplify right side
   1,288.69x = 4,538,897.09
5. Step 5: Solve for x
   x = 4,538,897.09/1,288.69
6. Step 6: Final answer
   x = 3,522.11