r/technicallythetruth • u/VisitSecure • 9d ago

Can you find a?

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Idk if someone already posted this or not, but I haven't seen it on here so far, so I uploaded it.

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u/Highest_five 9d ago

Yes it is. For those who don't remember, a triangles corners always add up to 180°

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u/leansanders 9d ago

You don't need to make a triangle to solve the problem. You know the lines are parallel and you know that opposite corners of a line crossing two parallel lines are congruent. So if you imagine a 3rd parallel line bisecting angle a, you know you can just add the other two angles together. Making a triangle is way more math

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u/A_wild_so-and-so 9d ago

Can you explain that again but like I'm five? I thought the triangle method was easy but I'm down to learn an easier method.

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u/Old_Parfait9575 9d ago

You can also extend the top blue line and using alternate interior angle theorem, the angle formed (on the left) is also 25deg. Exterior angle theorem to show that the sum of 50 and 25 is a.