Finding the Fourth Proportional to 1,390.76, 2,090.46 and 1,007.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.76 : 2,090.46 = 1,007.72 : x
2. Step 2: Convert to fraction form
   1,390.76/2,090.46 = 1,007.72/x
3. Step 3: Cross multiply
   1,390.76x = 2,090.46 × 1,007.72
4. Step 4: Simplify right side
   1,390.76x = 2,106,598.35
5. Step 5: Solve for x
   x = 2,106,598.35/1,390.76
6. Step 6: Final answer
   x = 1,514.71