Finding the Fourth Proportional to 1,990.31, 2,978.37 and 1,210.01

Step by Step Solution

1. Step 1: Write the proportion equation
   1,990.31 : 2,978.37 = 1,210.01 : x
2. Step 2: Convert to fraction form
   1,990.31/2,978.37 = 1,210.01/x
3. Step 3: Cross multiply
   1,990.31x = 2,978.37 × 1,210.01
4. Step 4: Simplify right side
   1,990.31x = 3,603,842.59
5. Step 5: Solve for x
   x = 3,603,842.59/1,990.31
6. Step 6: Final answer
   x = 1,810.70