Finding the Fourth Proportional to 1,128.74, 1,692.34 and 543.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,128.74 : 1,692.34 = 543.72 : x
2. Step 2: Convert to fraction form
   1,128.74/1,692.34 = 543.72/x
3. Step 3: Cross multiply
   1,128.74x = 1,692.34 × 543.72
4. Step 4: Simplify right side
   1,128.74x = 920,159.10
5. Step 5: Solve for x
   x = 920,159.10/1,128.74
6. Step 6: Final answer
   x = 815.21