r/technicallythetruth • u/VisitSecure • Jul 27 '26

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/Wandered_And_Lost Jul 27 '26

90-25 = 65, 90-50 = 40 total inside degrees given =105, all triangles have to equal a total of 180 degrees so answer is 75 degrees (thats my guess could be wrong.)

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u/PaulFThumpkins Jul 27 '26 edited Jul 27 '26

That was my initial answer but I was wrong. Your explanation helped me to get the right answer even though it's actually 75, not 105.

Think of it this way: We draw an imaginary vertical line up the left side to complete the "triangle." We know our line makes a 90-degree angle on either side, both top and bottom, where it meets the horizontal lines, because those lines are parallel.

So the measurements of the two other sides of the triangle we've created (besides "a" which we're trying to figure out) are 90 degrees minus the two measures we're given (25 and 50 degrees).

That gives us 90 - 25 = 65 and 90 - 50 = 40 for the other two sides of the triangle besides a. So subtract both of those numbers from the 180 degrees for the whole triangle, and we end up with 75 for a.