Finding the Fourth Proportional to 1,389.84, 2,082.42 and 978.24

Step by Step Solution

1. Step 1: Write the proportion equation
   1,389.84 : 2,082.42 = 978.24 : x
2. Step 2: Convert to fraction form
   1,389.84/2,082.42 = 978.24/x
3. Step 3: Cross multiply
   1,389.84x = 2,082.42 × 978.24
4. Step 4: Simplify right side
   1,389.84x = 2,037,106.54
5. Step 5: Solve for x
   x = 2,037,106.54/1,389.84
6. Step 6: Final answer
   x = 1,465.71