Question

Given : DEF Prove ∠ 1+∠ 2+∠ 3=180

Answer 1

i'm guessing DEF is a triangle and it's interior angles are 1, 2, and 3? what facts do you know about triangles?

Answer 2

that they equal 180

Answer 3

there you go! and one fun fact about geometry (in Euclidean geometry anyway) is that for any three points that are not all on the same line, you will have a triangle. and any triangle has an angle sum of 180. ^_^

Answer 4

now what kind of class is this for? just in case you are supposed to use theorems and stuff instead of just assuming it.

Answer 5

Geometry