Finding the Third Proportional to 9,139 and 19,987

Step by Step Solution

1. Step 1: Write the proportion equation
   9,139 : 19,987 = 19,987 : x
2. Step 2: Convert to fraction form
   9,139/19,987 = 19,987/x
3. Step 3: Cross multiply
   9,139x = 19,987 × 19,987
4. Step 4: Simplify right side
   9,139x = 399,480,169
5. Step 5: Solve for x
   x = 399,480,169/9,139
6. Step 6: Final answer
   x = 43,711.58