Finding the Third Proportional to 581.50 and 899.50

Step by Step Solution

1. Step 1: Write the proportion equation
   581.50 : 899.50 = 899.50 : x
2. Step 2: Convert to fraction form
   581.50/899.50 = 899.50/x
3. Step 3: Cross multiply
   581.50x = 899.50 × 899.50
4. Step 4: Simplify right side
   581.50x = 809,100.25
5. Step 5: Solve for x
   x = 809,100.25/581.50
6. Step 6: Final answer
   x = 1,391.40