Finding the Fourth Proportional to 1,139.47, 1,700.88 and 978.19

Step by Step Solution

1. Step 1: Write the proportion equation
   1,139.47 : 1,700.88 = 978.19 : x
2. Step 2: Convert to fraction form
   1,139.47/1,700.88 = 978.19/x
3. Step 3: Cross multiply
   1,139.47x = 1,700.88 × 978.19
4. Step 4: Simplify right side
   1,139.47x = 1,663,783.81
5. Step 5: Solve for x
   x = 1,663,783.81/1,139.47
6. Step 6: Final answer
   x = 1,460.14