help with Cartesian coordinate system, never heard of it?

Hi in my class we started diving into this cartesian system i have never heard if this and it seemed like no one else had eithier. I am about to take the final wenesday and have some questions i need to review. If you could help me with the problems below that would be awesome.(Rofl) ALso i know this is some easy looking stuff but its really nothing i have worked with before

1.)The distance between the two points http://webwork.linnbenton.edu/webwor...58bfad5fa1.png and http://webwork.linnbenton.edu/webwor...cd78a4d5f1.png is ?

2.)Find the distance between the two points, http://webwork.linnbenton.edu/webwor...199dda9bb1.png and http://webwork.linnbenton.edu/webwor...0923086e91.png

3.)Plot the points http://webwork.linnbenton.edu/webwor...78c69226d1.png, http://webwork.linnbenton.edu/webwor...c0a099a921.png, and http://webwork.linnbenton.edu/webwor...5929a443d1.png. Notice that these points are vertices of a right triangle (the angle http://webwork.linnbenton.edu/webwor...0fcdd79cd1.png is 90 degrees).

Find the distance between http://webwork.linnbenton.edu/webwor...0fcdd79cd1.png and http://webwork.linnbenton.edu/webwor...224e2cc9b1.png:

Find the distance between http://webwork.linnbenton.edu/webwor...0fcdd79cd1.png and http://webwork.linnbenton.edu/webwor...c23ba91971.png:

Find the area of the triangle http://webwork.linnbenton.edu/webwor...2433972481.png: