Finding the Third Proportional to 840 and 1,281.50

Step by Step Solution

1. Step 1: Write the proportion equation
   840 : 1,281.50 = 1,281.50 : x
2. Step 2: Convert to fraction form
   840/1,281.50 = 1,281.50/x
3. Step 3: Cross multiply
   840x = 1,281.50 × 1,281.50
4. Step 4: Simplify right side
   840x = 1,642,242.25
5. Step 5: Solve for x
   x = 1,642,242.25/840
6. Step 6: Final answer
   x = 1,955.05