Finding the Fourth Proportional to 31,187.70, 42,136.20 and 31,187.70

Step by Step Solution

1. Step 1: Write the proportion equation
   31,187.70 : 42,136.20 = 31,187.70 : x
2. Step 2: Convert to fraction form
   31,187.70/42,136.20 = 31,187.70/x
3. Step 3: Cross multiply
   31,187.70x = 42,136.20 × 31,187.70
4. Step 4: Simplify right side
   31,187.70x = 1,314,131,164.74
5. Step 5: Solve for x
   x = 1,314,131,164.74/31,187.70
6. Step 6: Final answer
   x = 42,136.20