Finding the Third Proportional to 851.50 and 2,120

Step by Step Solution

1. Step 1: Write the proportion equation
   851.50 : 2,120 = 2,120 : x
2. Step 2: Convert to fraction form
   851.50/2,120 = 2,120/x
3. Step 3: Cross multiply
   851.50x = 2,120 × 2,120
4. Step 4: Simplify right side
   851.50x = 4,494,400
5. Step 5: Solve for x
   x = 4,494,400/851.50
6. Step 6: Final answer
   x = 5,278.21