Finding the Fourth Proportional to 2,385.71, 3,558.72 and 1,998.21

Step by Step Solution

1. Step 1: Write the proportion equation
   2,385.71 : 3,558.72 = 1,998.21 : x
2. Step 2: Convert to fraction form
   2,385.71/3,558.72 = 1,998.21/x
3. Step 3: Cross multiply
   2,385.71x = 3,558.72 × 1,998.21
4. Step 4: Simplify right side
   2,385.71x = 7,111,069.89
5. Step 5: Solve for x
   x = 7,111,069.89/2,385.71
6. Step 6: Final answer
   x = 2,980.69