Finding the Fourth Proportional to 2,139.72, 3,210.00 and 907.13

Step by Step Solution

1. Step 1: Write the proportion equation
   2,139.72 : 3,210.00 = 907.13 : x
2. Step 2: Convert to fraction form
   2,139.72/3,210.00 = 907.13/x
3. Step 3: Cross multiply
   2,139.72x = 3,210.00 × 907.13
4. Step 4: Simplify right side
   2,139.72x = 2,911,891.92
5. Step 5: Solve for x
   x = 2,911,891.92/2,139.72
6. Step 6: Final answer
   x = 1,360.88