Finding the Fourth Proportional to 2,820.59, 3,888.35 and 1,978.67

Step by Step Solution

1. Step 1: Write the proportion equation
   2,820.59 : 3,888.35 = 1,978.67 : x
2. Step 2: Convert to fraction form
   2,820.59/3,888.35 = 1,978.67/x
3. Step 3: Cross multiply
   2,820.59x = 3,888.35 × 1,978.67
4. Step 4: Simplify right side
   2,820.59x = 7,693,761.32
5. Step 5: Solve for x
   x = 7,693,761.32/2,820.59
6. Step 6: Final answer
   x = 2,727.72