Finding the Fourth Proportional to 1,720.84, 2,578.74 and 853.42

Step by Step Solution

1. Step 1: Write the proportion equation
   1,720.84 : 2,578.74 = 853.42 : x
2. Step 2: Convert to fraction form
   1,720.84/2,578.74 = 853.42/x
3. Step 3: Cross multiply
   1,720.84x = 2,578.74 × 853.42
4. Step 4: Simplify right side
   1,720.84x = 2,200,748.29
5. Step 5: Solve for x
   x = 2,200,748.29/1,720.84
6. Step 6: Final answer
   x = 1,278.88