Finding the Fourth Proportional to 1,915.53, 2,643.48 and 1,216.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,915.53 : 2,643.48 = 1,216.50 : x
2. Step 2: Convert to fraction form
   1,915.53/2,643.48 = 1,216.50/x
3. Step 3: Cross multiply
   1,915.53x = 2,643.48 × 1,216.50
4. Step 4: Simplify right side
   1,915.53x = 3,215,793.42
5. Step 5: Solve for x
   x = 3,215,793.42/1,915.53
6. Step 6: Final answer
   x = 1,678.80