Finding the Third Proportional to 1,390.61 and 2,185.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.61 : 2,185.42 = 2,185.42 : x
2. Step 2: Convert to fraction form
   1,390.61/2,185.42 = 2,185.42/x
3. Step 3: Cross multiply
   1,390.61x = 2,185.42 × 2,185.42
4. Step 4: Simplify right side
   1,390.61x = 4,776,051.70
5. Step 5: Solve for x
   x = 4,776,051.70/1,390.61
6. Step 6: Final answer
   x = 3,434.51