Finding the Fourth Proportional to 1,992.12, 2,987.76 and 1,260.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,992.12 : 2,987.76 = 1,260.72 : x
2. Step 2: Convert to fraction form
   1,992.12/2,987.76 = 1,260.72/x
3. Step 3: Cross multiply
   1,992.12x = 2,987.76 × 1,260.72
4. Step 4: Simplify right side
   1,992.12x = 3,766,728.79
5. Step 5: Solve for x
   x = 3,766,728.79/1,992.12
6. Step 6: Final answer
   x = 1,890.81