Finding the Fourth Proportional to 2,120.42, 3,181.86 and 887.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,120.42 : 3,181.86 = 887.72 : x
2. Step 2: Convert to fraction form
   2,120.42/3,181.86 = 887.72/x
3. Step 3: Cross multiply
   2,120.42x = 3,181.86 × 887.72
4. Step 4: Simplify right side
   2,120.42x = 2,824,600.76
5. Step 5: Solve for x
   x = 2,824,600.76/2,120.42
6. Step 6: Final answer
   x = 1,332.09