Finding the Fourth Proportional to 1,987.16, 2,978.80 and 946.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,987.16 : 2,978.80 = 946.89 : x
2. Step 2: Convert to fraction form
   1,987.16/2,978.80 = 946.89/x
3. Step 3: Cross multiply
   1,987.16x = 2,978.80 × 946.89
4. Step 4: Simplify right side
   1,987.16x = 2,820,576.30
5. Step 5: Solve for x
   x = 2,820,576.30/1,987.16
6. Step 6: Final answer
   x = 1,419.40