Question

Can someone please help me?

The question is:
Write an indirect proof proving only one angle of an obtuse triangle is greater than 90°.

Answer 1

obtuse triangle is any thing from 91° to 179°

Answer 2

Bcoz sum of angles of a triangle is 180
And if one is greater than 90 then other two must sum up to (180- the third angle)
Since , the third angle is greater than 90
So, the remaining will sum less than 90
If two would be obtuse then it will ytend to form a quadrilateral