How to Find the Area of a Triangle Calculate the Area of a Triangle

Welcome to Math with Mr. In this video, I'm going to cover how to calculate the area of triangle. And remember, area is the amount of space two-dimensional or flat shape takes up. Our formula for finding area of triangles is at the top of your screen. / 2, and that means base * the height / 2. And that's going to give us the area of the triangles on your screen or any triangle that you are finding the area of. So, like just mentioned, you have some problems on your screen, and you have four of them that we are going to work through together. So, let's hop right in to number one. So, for number one here, the first thing we want to do is write out our formula for the area of triangle. So, area = base * height / 2. Now, whenever you have two letters right next to each other in math problem or in an algebra problem, that means multiplication. Okay? Again, two letters right next to each other, that means * base * height. So now, under our formula, we're going to plug in our base and height. So, our base of 5 in is down here. This is the base of our triangle. So, 5 * the height. Right? That 12 in. So, plug in the 12. And we divide that by two, and I'll tell you why at the end of this problem, why we divide by two. So now, it's time to solve. So, we know 5 * 12 is 60. And now, we need to do 60 / 2 to get to our answer. And notice, we have 60 / 2 written as fraction there. That's fine. fraction is division. So, that just means 60 / 2, which gets us to 30. Now, we need to put our unit of measure, which is inches. And we put two up here. And we read that as area = 30 sq in. And we make that And we make that square unit because there are square inches that cover that triangle to show how much space that figure takes up. So, area = 30 sq Now, Now, let's go back to why we divide by two. So, we have triangle here. I'm going to draw some imaginary lines to make this rectangle / parallelogram. So, in order to find the area of that parallelogram or rectangle, we would do 5 * 12, the base * the height or length * width. And that would get us 60. But this triangle is exactly half of that rectangle or half of that parallelogram. So, we divide by two to give us the area of the triangle or half of that rectangle or parallelogram. So, let's go to number two here. And we start by writing out our formula. Area = base * height / 2. Now, we plug in. Area = base is 14 here * the height of 5 We do not need the 10 or the 7. And then, we need to divide by two. So, area = well, 14 * 5 is 70. And we need to divide 70 by two to get our area. So, area = 35 squared. And again, we use square units because there are 35 sq 1 by 1 squares that cover that triangle or fill that area or space. So, for number three, let's start by writing out our formula. It's always good habit just to start by writing out the formula. So, we have area = base * height / 2. Now, hopefully, we know that we plug in next. So, base right here, the base of the triangle, is 9 * the height. How tall is that triangle? 3 ft. And we divide that by two. So, we get 9 * 3 is 27 / 2. So, our area And this one's actually going to give us decimal, 13 and 1/2 or 13 and 5/10 sq ft. And lastly, number four here. So, we start with the formula. Area = base * height / 2. Now, we need to plug in. So, our base down here is 5 yd. And we multiply it by our height. Now, our height is outside the triangle because we need to see how tall it is. That's fine. Due to the shape of the triangle, we have that measurement outside, but it still is the height. So, 5 yd * 6 yd and we divide that by two. So, we get area = 30 / 2. And area = 15 sq yd. So, there you have it. That's how you calculate the area of triangle. Base * height / 2. Hopefully, that helped out. Thanks so much for watching. Until next time. Peace.