Finding the Fourth Proportional to 1,390.34, 2,087.01 and 807.50

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.34 : 2,087.01 = 807.50 : x
2. Step 2: Convert to fraction form
   1,390.34/2,087.01 = 807.50/x
3. Step 3: Cross multiply
   1,390.34x = 2,087.01 × 807.50
4. Step 4: Simplify right side
   1,390.34x = 1,685,260.58
5. Step 5: Solve for x
   x = 1,685,260.58/1,390.34
6. Step 6: Final answer
   x = 1,212.12