Finding the Third Proportional to 7,815 and 10,042.50

Step by Step Solution

1. Step 1: Write the proportion equation
   7,815 : 10,042.50 = 10,042.50 : x
2. Step 2: Convert to fraction form
   7,815/10,042.50 = 10,042.50/x
3. Step 3: Cross multiply
   7,815x = 10,042.50 × 10,042.50
4. Step 4: Simplify right side
   7,815x = 100,851,806.25
5. Step 5: Solve for x
   x = 100,851,806.25/7,815
6. Step 6: Final answer
   x = 12,904.90