Finding the Fourth Proportional to 1,987.62, 2,978.13 and 1,216.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,987.62 : 2,978.13 = 1,216.50 : x
2. Step 2: Convert to fraction form
   1,987.62/2,978.13 = 1,216.50/x
3. Step 3: Cross multiply
   1,987.62x = 2,978.13 × 1,216.50
4. Step 4: Simplify right side
   1,987.62x = 3,622,895.15
5. Step 5: Solve for x
   x = 3,622,895.15/1,987.62
6. Step 6: Final answer
   x = 1,822.73