Finding the Fourth Proportional to 2,155, 2,973.90 and 1,223.50

Step by Step Solution

1. Step 1: Write the proportion equation
   2,155 : 2,973.90 = 1,223.50 : x
2. Step 2: Convert to fraction form
   2,155/2,973.90 = 1,223.50/x
3. Step 3: Cross multiply
   2,155x = 2,973.90 × 1,223.50
4. Step 4: Simplify right side
   2,155x = 3,638,566.65
5. Step 5: Solve for x
   x = 3,638,566.65/2,155
6. Step 6: Final answer
   x = 1,688.43