Complementary Angles Supplementary Angles Math with Mr J

Welcome to Math with Mr. In this video, I'm going to cover complementary and supplementary angles. I'm going to talk about what those words mean, and then we're also going to take look at how to find missing complementary angles and missing supplementary angles. We have two complementary examples and two supplementary examples. So, let's jump right in to number one. For number one, we have complementary angles. Complementary angles are angles that add up to equal exactly 90°. So, for number one, we're given 70° angle. We need to figure out what this equals to equal 90°. So, 70 plus what equals 90°? And some of these are harder than others, so some you may be able to figure out using mental math, some you may not. So, what we can do, we take the 90° that we want to get to and subtract what we're given. We're given that 70°. That's That's our known. Subtract these, and that difference is what is going to equal. So, 90° - 70° equals 20°. So, equals 20°. And let's double-check. 70°, what we were given, plus that 20°, gives us 90°. Again, complementary angles add add up to equal exactly 90°. Number two. These are complementary angles as well. We have known here. We're given 48°, so we need to find what equals. So, we can take our 90° that we want to get to, subtract what we're given, and that difference will be what equals. So, 90 - 48° gives us 42°. So, equals 42°. plus this 48 equals 90°. So, 48° angle and 42° angle are complementary. Number three and number four, we're going to move to supplementary angles. Supplementary angles have to equal 180°. So, for number three, we have 65° angle. We need to find what angle equals in order to get to 180°. So, we use the same strategy. We can use our 180, subtract our given or known, 65°. 180 - 65 = 115°. So, = 115°. So, let's double-check that 115° plus the known of 65° equals exactly 180°, so that 115 and 65° angle are supplementary. So, let's move on to number four, where we are given 128°, and we need to find what angle equals. These are supplementary angles, so we know they have to equal 180°. Let's subtract what we're given, 128°, and that gives us 52°. So, = 52°. And 52 + 128° equals exactly 180, so they are supplementary. Now, one thing do want to mention before we end here, this is how remember which is which as far as complementary and supplementary. The here is lower letter in the alphabet, so it aligns with the lower number. is further along in the alphabet than so it aligns with the higher number. So, there you have it. There's complementary and supplementary angles. hope that helped. Thanks so much for watching. Until next time, peace.