Finding the Third Proportional to 3,991.70 and 8,530.15

Step by Step Solution

1. Step 1: Write the proportion equation
   3,991.70 : 8,530.15 = 8,530.15 : x
2. Step 2: Convert to fraction form
   3,991.70/8,530.15 = 8,530.15/x
3. Step 3: Cross multiply
   3,991.70x = 8,530.15 × 8,530.15
4. Step 4: Simplify right side
   3,991.70x = 72,763,532.33
5. Step 5: Solve for x
   x = 72,763,532.33/3,991.70
6. Step 6: Final answer
   x = 18,228.70