Finding the Fourth Proportional to 1,137.90, 1,570.72 and 665.94

Step by Step Solution

1. Step 1: Write the proportion equation
   1,137.90 : 1,570.72 = 665.94 : x
2. Step 2: Convert to fraction form
   1,137.90/1,570.72 = 665.94/x
3. Step 3: Cross multiply
   1,137.90x = 1,570.72 × 665.94
4. Step 4: Simplify right side
   1,137.90x = 1,046,005.28
5. Step 5: Solve for x
   x = 1,046,005.28/1,137.90
6. Step 6: Final answer
   x = 919.25