How to Find Scale Factor with Similar Figures

well you want to know whether you're finding the scale factor from this figure on the left to this figure on the right or if you're going from the figure on the right to the figure on the left so that's very important is the direction that you're scaling the figure and the formula like to remember this is just simple way of doing it is just think about new / old so if I'm going from this triangle to this triangle this is my new triangle and I'm going to divide by the old triangle now what you want to do if the figures are similar and they tell you that in the problem you want to match up the corresponding side so say for example if I'm comparing four and ten I'm going from four to ten what am multiplying by to get from four to ten that's my scale factor so the easiest way to do this would just be to take the new length which is ten divided by the old length which is four and you can see that's giving us scale factor of five divided by two which is two and half so this is going to be two-and-a-half times you know the scaled okay so the size are two and half times longer now the one way that you can tell your fear on the right track is if the scale factor is greater than one then that means it's an enlargement it's getting bigger so enlargement now if the scale factor is less than one okay like half or third or something like that then it's reduction it's getting smaller so if we're going from this figure to this figure okay now this would be the new length that's for the old length was ten now we're looking at scale factor of 2/5 and you can see 2/5 is less than 1 so you can see that this is reduction and it makes sense because you can see this figures you know lot smaller but notice that these are reciprocals of each other so even if you mix it up and you say well got to fist but it doesn't make sense this figure is larger I'm going from here to here it should be you know all you have to do is just take the reciprocal and you realize all the scale factor is 5 halves so that's how you work with scale factor it's very simple again just pay attention to the direction that you're going and use the formula new divided by old and you got it so subscribe to the channel check out more math tutoring videos on my youtube channel Mario's math tutoring and look forward to helping you in the future videos I'll talk to you soon