Finding the Fourth Proportional to 2,153.96, 2,972.78 and 1,315.15

Step by Step Solution

1. Step 1: Write the proportion equation
   2,153.96 : 2,972.78 = 1,315.15 : x
2. Step 2: Convert to fraction form
   2,153.96/2,972.78 = 1,315.15/x
3. Step 3: Cross multiply
   2,153.96x = 2,972.78 × 1,315.15
4. Step 4: Simplify right side
   2,153.96x = 3,909,654.12
5. Step 5: Solve for x
   x = 3,909,654.12/2,153.96
6. Step 6: Final answer
   x = 1,815.10