Finding the Fourth Proportional to 1,137.51, 1,569.76 and 640.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,137.51 : 1,569.76 = 640.15 : x
2. Step 2: Convert to fraction form
   1,137.51/1,569.76 = 640.15/x
3. Step 3: Cross multiply
   1,137.51x = 1,569.76 × 640.15
4. Step 4: Simplify right side
   1,137.51x = 1,004,870.81
5. Step 5: Solve for x
   x = 1,004,870.81/1,137.51
6. Step 6: Final answer
   x = 883.40