Finding the Fourth Proportional to 1,091.80, 1,638.42 and 652.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,091.80 : 1,638.42 = 652.72 : x
2. Step 2: Convert to fraction form
   1,091.80/1,638.42 = 652.72/x
3. Step 3: Cross multiply
   1,091.80x = 1,638.42 × 652.72
4. Step 4: Simplify right side
   1,091.80x = 1,069,429.50
5. Step 5: Solve for x
   x = 1,069,429.50/1,091.80
6. Step 6: Final answer
   x = 979.51