Finding the Fourth Proportional to 1,388.50, 1,916.16 and 767.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,388.50 : 1,916.16 = 767.50 : x
2. Step 2: Convert to fraction form
   1,388.50/1,916.16 = 767.50/x
3. Step 3: Cross multiply
   1,388.50x = 1,916.16 × 767.50
4. Step 4: Simplify right side
   1,388.50x = 1,470,652.80
5. Step 5: Solve for x
   x = 1,470,652.80/1,388.50
6. Step 6: Final answer
   x = 1,059.17