Question

Can someone help me write and Indirect Proof for this statement:

The two non-right angles of a right triangle measure less than 90 degrees.

Answer 1

We can do a proof by contradiction.
Assume the negation of the claim you want to prove.

So we assume that the two non right angles of the triangle do measure 90 or greater.
( the negation of less than 90 is 90 or more )

can we now derive a contradiction?

Answer 2

we know there is already a 90 degree angle

Answer 3

so you have now 3 angles that measure 90 degrees (or more)

Answer 4

I guess we can derive a contradiction? I'm sorry I'm very clueless to what is being said.

Answer 5

hint, a euclidean triangle must add to 180 degrees (any triangle, no matter what kind of triangle)

Answer 6

okay?

Answer 7

ok so lets draw this triangle
we negated the claim

Answer 8

90 degree triangle

Answer 9

Negate the statement:
The two non-right angles of a right triangle measure less than 90 degrees.

You get

Either of the two non-right angles of a triangle can measure 90 degrees