Finding the Fourth Proportional to 1,036.08, 1,430.06 and 642.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,036.08 : 1,430.06 = 642.89 : x
2. Step 2: Convert to fraction form
   1,036.08/1,430.06 = 642.89/x
3. Step 3: Cross multiply
   1,036.08x = 1,430.06 × 642.89
4. Step 4: Simplify right side
   1,036.08x = 919,360.91
5. Step 5: Solve for x
   x = 919,360.91/1,036.08
6. Step 6: Final answer
   x = 887.35