Finding the Third Proportional to 1,065 and 1,390.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,065 : 1,390.50 = 1,390.50 : x
2. Step 2: Convert to fraction form
   1,065/1,390.50 = 1,390.50/x
3. Step 3: Cross multiply
   1,065x = 1,390.50 × 1,390.50
4. Step 4: Simplify right side
   1,065x = 1,933,490.25
5. Step 5: Solve for x
   x = 1,933,490.25/1,065
6. Step 6: Final answer
   x = 1,815.48