Finding the Fourth Proportional to 1,109.70, 1,531.52 and 661.69

Step by Step Solution

1. Step 1: Write the proportion equation
   1,109.70 : 1,531.52 = 661.69 : x
2. Step 2: Convert to fraction form
   1,109.70/1,531.52 = 661.69/x
3. Step 3: Cross multiply
   1,109.70x = 1,531.52 × 661.69
4. Step 4: Simplify right side
   1,109.70x = 1,013,392.56
5. Step 5: Solve for x
   x = 1,013,392.56/1,109.70
6. Step 6: Final answer
   x = 913.21