Finding the Fourth Proportional to 1,428.83, 1,970.90 and 980.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,428.83 : 1,970.90 = 980.50 : x
2. Step 2: Convert to fraction form
   1,428.83/1,970.90 = 980.50/x
3. Step 3: Cross multiply
   1,428.83x = 1,970.90 × 980.50
4. Step 4: Simplify right side
   1,428.83x = 1,932,460.05
5. Step 5: Solve for x
   x = 1,932,460.05/1,428.83
6. Step 6: Final answer
   x = 1,352.48