Finding the Fourth Proportional to 1,980.78, 2,971.80 and 1,056.30

Step by Step Solution

1. Step 1: Write the proportion equation
   1,980.78 : 2,971.80 = 1,056.30 : x
2. Step 2: Convert to fraction form
   1,980.78/2,971.80 = 1,056.30/x
3. Step 3: Cross multiply
   1,980.78x = 2,971.80 × 1,056.30
4. Step 4: Simplify right side
   1,980.78x = 3,139,112.34
5. Step 5: Solve for x
   x = 3,139,112.34/1,980.78
6. Step 6: Final answer
   x = 1,584.79