Finding the Third Proportional to 690 and 1,055.50

Step by Step Solution

1. Step 1: Write the proportion equation
   690 : 1,055.50 = 1,055.50 : x
2. Step 2: Convert to fraction form
   690/1,055.50 = 1,055.50/x
3. Step 3: Cross multiply
   690x = 1,055.50 × 1,055.50
4. Step 4: Simplify right side
   690x = 1,114,080.25
5. Step 5: Solve for x
   x = 1,114,080.25/690
6. Step 6: Final answer
   x = 1,614.61