Finding the Fourth Proportional to 3,700.78, 5,106.90 and 2,128.84

Step by Step Solution

1. Step 1: Write the proportion equation
   3,700.78 : 5,106.90 = 2,128.84 : x
2. Step 2: Convert to fraction form
   3,700.78/5,106.90 = 2,128.84/x
3. Step 3: Cross multiply
   3,700.78x = 5,106.90 × 2,128.84
4. Step 4: Simplify right side
   3,700.78x = 10,871,773.00
5. Step 5: Solve for x
   x = 10,871,773.00/3,700.78
6. Step 6: Final answer
   x = 2,937.70