Finding the Fourth Proportional to 1,320.58, 1,820.91 and 987.94

Step by Step Solution

1. Step 1: Write the proportion equation
   1,320.58 : 1,820.91 = 987.94 : x
2. Step 2: Convert to fraction form
   1,320.58/1,820.91 = 987.94/x
3. Step 3: Cross multiply
   1,320.58x = 1,820.91 × 987.94
4. Step 4: Simplify right side
   1,320.58x = 1,798,949.83
5. Step 5: Solve for x
   x = 1,798,949.83/1,320.58
6. Step 6: Final answer
   x = 1,362.24