Finding the Fourth Proportional to 1,007.91, 1,510.01 and 641.93

Step by Step Solution

1. Step 1: Write the proportion equation
   1,007.91 : 1,510.01 = 641.93 : x
2. Step 2: Convert to fraction form
   1,007.91/1,510.01 = 641.93/x
3. Step 3: Cross multiply
   1,007.91x = 1,510.01 × 641.93
4. Step 4: Simplify right side
   1,007.91x = 969,312.37
5. Step 5: Solve for x
   x = 969,312.37/1,007.91
6. Step 6: Final answer
   x = 961.71