Finding the Fourth Proportional to 1,398.82, 1,931.12 and 980.45

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.82 : 1,931.12 = 980.45 : x
2. Step 2: Convert to fraction form
   1,398.82/1,931.12 = 980.45/x
3. Step 3: Cross multiply
   1,398.82x = 1,931.12 × 980.45
4. Step 4: Simplify right side
   1,398.82x = 1,893,373.88
5. Step 5: Solve for x
   x = 1,893,373.88/1,398.82
6. Step 6: Final answer
   x = 1,353.55