Thank you so much to everyone that is helping me

Find the area of the triangle with vertices http://mathcs.chapman.edu/webwork2_f...984cec8771.png, http://mathcs.chapman.edu/webwork2_f...9e21732301.png, and http://mathcs.chapman.edu/webwork2_f...e424343f71.png

so for this one i found 2 vectors

4i-j+0k

-6i+10j+0k

took the cross product of the two to get 40k - (6k) which equals 34k, so

where am i going wrong?