Finding the Third Proportional to 7,840 and 12,516

Step by Step Solution

1. Step 1: Write the proportion equation
   7,840 : 12,516 = 12,516 : x
2. Step 2: Convert to fraction form
   7,840/12,516 = 12,516/x
3. Step 3: Cross multiply
   7,840x = 12,516 × 12,516
4. Step 4: Simplify right side
   7,840x = 156,650,256
5. Step 5: Solve for x
   x = 156,650,256/7,840
6. Step 6: Final answer
   x = 19,980.90