Finding the Fourth Proportional to 1,250.56, 1,876.16 and 428.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,250.56 : 1,876.16 = 428.72 : x
2. Step 2: Convert to fraction form
   1,250.56/1,876.16 = 428.72/x
3. Step 3: Cross multiply
   1,250.56x = 1,876.16 × 428.72
4. Step 4: Simplify right side
   1,250.56x = 804,347.32
5. Step 5: Solve for x
   x = 804,347.32/1,250.56
6. Step 6: Final answer
   x = 643.19