Finding the Missing Angle of a Quadrilateral Math with Mr J

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Finding the Missing Angle of a Quadrilateral Math with Mr J

Math with Mr. J · ⏱ 3:12 · 279.2K مشاهدة · 5 years ago

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Welcome to Math with Mr. In this video, I'm going to cover how to find the missing angle within quadrilateral. And we have two examples that we're going to go through together in order to get this down. Now, very important note at the top of your screen, when we're working with quadrilaterals, when you add all four angles up, it has to equal 360°, no matter what type of quadrilateral or what it looks like, the magic number is 360°. So, let's jump right into number one where our missing angle is in the bottom right here, represented by that variable So, we need to take look at our knowns. We know we have 120°, 100, and 80. So, the first thing we do is add up those unknowns. So, 120° + 100 + 80. So, if we add those up, we get 300°. So, we need to get to 360. So, we take what we need to get to 360° and subtract the 300°, what we know. That will give us what our unknown is. So, 360° - 300° = 60°. So, = 60°. That's our missing or unknown angle. And it works because if we take look at it algebraically, if we do 100° + 120° + 80° + it will have to give us 360°. So, what we do, we isolate our variable. We add all of these up and subtract them from 360, and that gives us what equals. So, let's take look at number two and do another example. So, our unknown is in the top right, represented by So, let's take what we do know, the 70, 132, and 81°, add them up, and then subtract from 360. So, + 81° + 70° = 283°. So, now, we need to do 360, what we need to get to, - what we have, and see what our missing angle is. So, little bit of borrowing action here, and we get 77°. So, = 77°. So, just to recap, add up all of your known angle measures, and then subtract that from 360, and that will give you your missing angle. hope that helped. Thanks so much for watching. Until next time, peace.