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Why don't my triangles add up to 180 degrees? Exterior angle theorem?

Why don't my triangles add up to 180 degrees? Exterior angle theorem? Topic: Exterior homeworks
June 19, 2019 / By Cybill
Question: I'm doing this geometry homework and when I solve for x of the exterior angle and then add up all the angles of the triangle, it doesn't add up to 180. I've done like 4 of them and they don't add up to 180! Here's an example: The sides of a triangle are 80 degrees, x degrees, and the exterior angle is (3x-22) degrees. There's nothing next to the exterior angle, it's at the top of the triangle, and the other two measurements are at the bottom corners of the triangle. I keep on getting that x = 51 and that the exterior angle equals 131 degrees but then when you add 80, 51, and 131, that does not equal 180. I'm so stressed. What am I doing wrong?!
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Best Answers: Why don't my triangles add up to 180 degrees? Exterior angle theorem?

Originally Answered: What is the common angle and height of these two triangles?
If you have a line of slope m, and θ is the angle it makes with the x-axis, then tan(θ) = m. So you can use tan^-1(m), the inverse tangent (sometimes written as the arctangent, "arctan(m)"), to find the degree measure. This is because if you draw a right triangle from the angle, the rise/run ratio is the same as the side opposite of the angle divided by the adjacent side. This is the tangent function in trigonometry. For example, if you have a line of slope 1, then the angle it makes is tan^-1(1) = 45 degrees. Most scientific calculators will have an inverse tangent function. Microsoft Excel also has an ATAN(number) function, though it gives the result in radians. You have to convert it to degrees by entering "=+DEGREES(ATAN(1))" for example to get back 45.
Originally Answered: What is the common angle and height of these two triangles?
This Site Might Help You. RE: How to convert rise over run to an angle in degrees? I am working on some aircraft geometry in a CAD program and my numbers don't work with my hand drawn angles. I've checked everything using the Pythagorean Theorem and Sin and Cos, now I need to convert these numbers to angles. So using rise over run how do I find the angle of the...

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