Finding the Fourth Proportional to 1,977.42, 2,728.98 and 1,388.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,977.42 : 2,728.98 = 1,388.10 : x
2. Step 2: Convert to fraction form
   1,977.42/2,728.98 = 1,388.10/x
3. Step 3: Cross multiply
   1,977.42x = 2,728.98 × 1,388.10
4. Step 4: Simplify right side
   1,977.42x = 3,788,097.14
5. Step 5: Solve for x
   x = 3,788,097.14/1,977.42
6. Step 6: Final answer
   x = 1,915.68