Math Is Fun Forum

Toast

Real Member

Registered: 2006-10-08

Posts: 1,321

SAS or RHS?

If we have the two attached diagrams, what should the proof be?
The answer says its RHS, although I think SAS would be more applicable, seeing as (although you can easily work it out) the hypotenuse is not initially given.

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: SAS or RHS?

If you're allowed to assume that both triangles have a right angle, then SAS is clearly the best way to go because you don't need to find anything else.

But if you're not given that those are right-angles, then no matter which proof you use, you're always going to have to work out something. In that case, the simplest way would probably be to show that the bottom triangle has a third length of 17 and then prove it by SSS, because that way you don't have any trig involved.

I definitely wouldn't use RHS, because that would require you to show that both triangles had right angles AND that the bottom triangle had a hypotenuse of 17, which is more work than is needed.

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Why did the vector cross the road?
It wanted to be normal.

Toast

Real Member

Registered: 2006-10-08

Posts: 1,321

Re: SAS or RHS?

Woops, I forgot to put in a right angle, there's supposed to be one in both questions. lol