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Mugwump303 wrote:Is there a different way than to guess and check? Or is that the only way?
Mugwump303 wrote:One question. How do we know that the line at the bottom of the right triangle is parallel to the line crossing the center?
And by the "line at the bottom of the right triangle" I mean the line that makes up the 90 degree angle of the biggest triangle. And by the "line crossing the center" I mean the line that goes from B to O to the other side of the circle.
But then how do you know that E is 50 degrees? You'd have to think that the smaller triangle is a right triangle. But how do you know that the smaller triangle is a right triangle?pemdas wrote:who you are asking?
my solution doesn't show any parallelism :roll:
why you'd bother with such kind of info, when it's simple and laid right in front of you
[spoiler]if GMAT question takes you more than 2 minutes even the hardest one, something is wrong with your approach or you are missing concept needed to apply for this question
[/spoiler]Mugwump303 wrote:One question. How do we know that the line at the bottom of the right triangle is parallel to the line crossing the center?
And by the "line at the bottom of the right triangle" I mean the line that makes up the 90 degree angle of the biggest triangle. And by the "line crossing the center" I mean the line that goes from B to O to the other side of the circle.
Well actually, finding the 20 was what I had a problem with. If we know that E is 50 degrees then we just have 20 + 50 + 90 + ? = 180. ? = 20. But what I don't understand is how we know that E is 50 degrees. We could only know this if we're sure that the small triangle inside the big triangle is a right triangle. But how are we sure that it is?LalaB wrote:everyone easily found angle 20.
what I do next-
see the very small triangle near x. here we found that one of its angle is 20, x and another angle of that triangle are vertical (so, they are equal)
so now we know that angles of that small triangle are-
20+x+90=180
x=70
How did you find the 20 degree angle of the small triangle then?LalaB wrote:@Mugwump303
I didnt mean the triangle with E.(so, no need to find E)
my triangle is veerrry small and next to x angle.
please see above the pic attached by pemdas. please take a look at the triangle with angles 20-20-140Mugwump303 wrote:How did you find the 20 degree angle of the small triangle then?LalaB wrote:@Mugwump303
I didnt mean the triangle with E.(so, no need to find E)
my triangle is veerrry small and next to x angle.
Here's the thing I don't get. How do we know that the smaller triangle has to have all the same angles as the big triangle? That would mean that the line that goes through OB is parallel to the line at the base of the big triangle. But why does that have to be? Is there some property of circles, triangles or angles that I don't know about?LalaB wrote:I am sorry, but I have no headphones. so, I watched ur video without a sound. hope I got what u asked in that video )))
please take a look at the big right triangle, and the triangle with angle E. see they are similar (here u can find the discussion of similar triangles-https://www.beatthegmat.com/triangle-2-d ... tml#439081). it means that the triangle with angle E must be a right triangle also )
hope it helps
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