Finding the Third Proportional to 821.75 and 1,155.50

Step by Step Solution

1. Step 1: Write the proportion equation
   821.75 : 1,155.50 = 1,155.50 : x
2. Step 2: Convert to fraction form
   821.75/1,155.50 = 1,155.50/x
3. Step 3: Cross multiply
   821.75x = 1,155.50 × 1,155.50
4. Step 4: Simplify right side
   821.75x = 1,335,180.25
5. Step 5: Solve for x
   x = 1,335,180.25/821.75
6. Step 6: Final answer
   x = 1,624.80