Finding the Third Proportional to 871.50 and 1,140

Step by Step Solution

1. Step 1: Write the proportion equation
   871.50 : 1,140 = 1,140 : x
2. Step 2: Convert to fraction form
   871.50/1,140 = 1,140/x
3. Step 3: Cross multiply
   871.50x = 1,140 × 1,140
4. Step 4: Simplify right side
   871.50x = 1,299,600
5. Step 5: Solve for x
   x = 1,299,600/871.50
6. Step 6: Final answer
   x = 1,491.22