Finding the Third Proportional to 17,878.50 and 21,172.50

Step by Step Solution

1. Step 1: Write the proportion equation
   17,878.50 : 21,172.50 = 21,172.50 : x
2. Step 2: Convert to fraction form
   17,878.50/21,172.50 = 21,172.50/x
3. Step 3: Cross multiply
   17,878.50x = 21,172.50 × 21,172.50
4. Step 4: Simplify right side
   17,878.50x = 448,274,756.25
5. Step 5: Solve for x
   x = 448,274,756.25/17,878.50
6. Step 6: Final answer
   x = 25,073.40