Which set can not reprsent the lengths of the sides of a triangle?

Question

a){4,5,6} 2){5,5,11) 3){7,7,12} 4){8,8,8}

The coordinates of Point R are (-3,2) and the coordinates of point T are (4,1). What is the length of RT?

Answer 1

to have a triangle, the sum of any two of the sides must be greater than the third side.
so look at 5,5,11, is 5+5 > 11 ?

for the second, use your "distance between two points" formula.

http://www.purplemath.com/modules/distform.htm

look at the example half way down the page, it fits your problem exactly.