Finding the Fourth Proportional to 1,538.51, 2,122.49 and 978.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,538.51 : 2,122.49 = 978.80 : x
2. Step 2: Convert to fraction form
   1,538.51/2,122.49 = 978.80/x
3. Step 3: Cross multiply
   1,538.51x = 2,122.49 × 978.80
4. Step 4: Simplify right side
   1,538.51x = 2,077,488.32
5. Step 5: Solve for x
   x = 2,077,488.32/1,538.51
6. Step 6: Final answer
   x = 1,350.32