Finding the Third Proportional to 1,388.81 and 2,111.91

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.81 : 2,111.91 = 2,111.91 : x
2. Step 2: Convert to fraction form
   1,388.81/2,111.91 = 2,111.91/x
3. Step 3: Cross multiply
   1,388.81x = 2,111.91 × 2,111.91
4. Step 4: Simplify right side
   1,388.81x = 4,460,148.01
5. Step 5: Solve for x
   x = 4,460,148.01/1,388.81
6. Step 6: Final answer
   x = 3,211.48