Finding the Fourth Proportional to 1,987.29, 2,979.72 and 947.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,987.29 : 2,979.72 = 947.61 : x
2. Step 2: Convert to fraction form
   1,987.29/2,979.72 = 947.61/x
3. Step 3: Cross multiply
   1,987.29x = 2,979.72 × 947.61
4. Step 4: Simplify right side
   1,987.29x = 2,823,612.47
5. Step 5: Solve for x
   x = 2,823,612.47/1,987.29
6. Step 6: Final answer
   x = 1,420.84