Finding the Fourth Proportional to 1,127.79, 1,690.05 and 715.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,127.79 : 1,690.05 = 715.89 : x
2. Step 2: Convert to fraction form
   1,127.79/1,690.05 = 715.89/x
3. Step 3: Cross multiply
   1,127.79x = 1,690.05 × 715.89
4. Step 4: Simplify right side
   1,127.79x = 1,209,889.89
5. Step 5: Solve for x
   x = 1,209,889.89/1,127.79
6. Step 6: Final answer
   x = 1,072.80