Question

Which pair of angles cannot be used to create an obtuse triangle?

A.
70° and 25°

B.
45° and 35°

C.
50° and 25°

D.
20° and 15°

Answer 1

A. 70 and 25

Explanation:

this is because for it to be obtuse, the third angle must be larger than 90 degrees. and to find that out you must know that all triangles if the three angles are added together you get 180 degrees. then you do 70 + 25 which is 95 so the third angle must be 85 which is less than 90 not more.

Another example is if I do this with B, 45+35=80 and 180-80=100 so the 3rd angle on triangle B is 100 degrees which is more than 90 so it IS obtuse