Finding the Fourth Proportional to 1,209.02, 1,667.51 and 810.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,209.02 : 1,667.51 = 810.55 : x
2. Step 2: Convert to fraction form
   1,209.02/1,667.51 = 810.55/x
3. Step 3: Cross multiply
   1,209.02x = 1,667.51 × 810.55
4. Step 4: Simplify right side
   1,209.02x = 1,351,596.18
5. Step 5: Solve for x
   x = 1,351,596.18/1,209.02
6. Step 6: Final answer
   x = 1,117.93