Finding the Fourth Proportional to 1,942.70, 2,912.59 and 915.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,942.70 : 2,912.59 = 915.50 : x
2. Step 2: Convert to fraction form
   1,942.70/2,912.59 = 915.50/x
3. Step 3: Cross multiply
   1,942.70x = 2,912.59 × 915.50
4. Step 4: Simplify right side
   1,942.70x = 2,666,476.15
5. Step 5: Solve for x
   x = 2,666,476.15/1,942.70
6. Step 6: Final answer
   x = 1,372.56