Finding the Fourth Proportional to 1,553.02, 2,142.80 and 1,428.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,553.02 : 2,142.80 = 1,428.55 : x
2. Step 2: Convert to fraction form
   1,553.02/2,142.80 = 1,428.55/x
3. Step 3: Cross multiply
   1,553.02x = 2,142.80 × 1,428.55
4. Step 4: Simplify right side
   1,553.02x = 3,061,089.80
5. Step 5: Solve for x
   x = 3,061,089.80/1,553.02
6. Step 6: Final answer
   x = 1,971.06