My cousin is scared to talk to the boys at our party cus she thinks even though they are related they are mean. Should she go back there and talk to them, or should me or cousin 2 go with her.

Don't force her let her ease into maybe getting comfortable enough to talk to the boys. Give some encouraging words for moral support but don't push it and don't go on your own without her. There will be plenty of more times to talk to different boys. Hope you have a great party.

step-by-step explanation:

assume that you have 3 different side lengths.   apply the pythagorean theorem here:   square each of the two shortest sides; call them a and b, so that their squares are a² and b².   also square the longest side, calling the result c².

now, if a² + b² = c² is true, the triangle is a right triangle; otherwise it is not a right triangle.