Finding the Fourth Proportional to 1,298.67, 1,792.15 and 709.21

Step by Step Solution

1. Step 1: Write the proportion equation
   1,298.67 : 1,792.15 = 709.21 : x
2. Step 2: Convert to fraction form
   1,298.67/1,792.15 = 709.21/x
3. Step 3: Cross multiply
   1,298.67x = 1,792.15 × 709.21
4. Step 4: Simplify right side
   1,298.67x = 1,271,015.21
5. Step 5: Solve for x
   x = 1,271,015.21/1,298.67
6. Step 6: Final answer
   x = 978.70