Finding the Fourth Proportional to 1,421.63, 1,961.86 and 783.59

Step by Step Solution

1. Step 1: Write the proportion equation
   1,421.63 : 1,961.86 = 783.59 : x
2. Step 2: Convert to fraction form
   1,421.63/1,961.86 = 783.59/x
3. Step 3: Cross multiply
   1,421.63x = 1,961.86 × 783.59
4. Step 4: Simplify right side
   1,421.63x = 1,537,300.50
5. Step 5: Solve for x
   x = 1,537,300.50/1,421.63
6. Step 6: Final answer
   x = 1,081.36