Finding the Fourth Proportional to 1,090.68, 1,634.34 and 678.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,090.68 : 1,634.34 = 678.72 : x
2. Step 2: Convert to fraction form
   1,090.68/1,634.34 = 678.72/x
3. Step 3: Cross multiply
   1,090.68x = 1,634.34 × 678.72
4. Step 4: Simplify right side
   1,090.68x = 1,109,259.24
5. Step 5: Solve for x
   x = 1,109,259.24/1,090.68
6. Step 6: Final answer
   x = 1,017.03