### Video instructions and help with filling out and completing Which Form 8815 Calculators

**Instructions and Help about Which Form 8815 Calculators**

Hi everyone and welcome to this video today I'm going to explain to you how to calculate a gradient now before you do something like that it's always very important to know what you are doing because that would make it easier to remember now the gradient is basically how steep a slope is between two different places now that is the simplest way of explaining it so the formula is gradient equals vertical interval over horizontal equivalent now what does this tell you it tells you the vertical interval is the difference in height between those two locations on the map so it's a simple calculation 200 minus 140 or something like that and the horizontal equivalent is simply the distance between those two places so you are going to calculate if you have 25 centimeters on your map then you are going to calculate the real distance between those two places so let's have a look at our map so here we have a few contour lines now it's important to understand what they represent a contour line is a line that connects every place with the same altitude so in other words on this line here for example each and every place on the line doesn't matter where we go it could be here it could be there or yet every single place on this line is 1020 meters above sea level right so your teacher might ask you to calculate the gradient between point a and point B now first thing you need to know is what is the height point a so this there are no numbers on this side of the map but if you just trace this line if you go all along this line you'll see that it's 1020 because every place on this line is 1020 so that's your first number 1020 meters and then you want to know what is the height of this specific place over here and you'll see that it's 1,100 meters above sea level the next thing you need to know is the distance between these two places and here it's not really 25 but let's say it's 25 centimeters and so what you're going to do is you are going to calculate the real distance now I posted a video on the distance calculation using different map scales so if you'd like to see that click the link below but I'm not going to go into too much detail what you're going to do here is you're going to say 25 centimeters times the scale it will give you a certain number and we'll take it from there so let's look at how it's done so firstly we want to find the difference in height so it's a 1100-1200 eater's times 15,000 so remember we always use the scale when we calculate the real distance now 1100 minus 1020 is 80 meters that's very easy and here we have to do a little calculation this will give you a total of 1,250,000 centimeters now obviously you want to convert centimeters to kilometers so how do we do this we say 1 250,000 divided by a hundred thousand and this will give you so it's just right that amount this will give you a total of twelve comma five kilometers now obviously this we are going to write the final answer as a ratio and that is why we can't compare meters with kilometers and that is why we are going to convert this to meters so this would give you I don't have enough space to write everything out but this is 12,500 meters 12,500 meters now we want to simplify these numbers and so what we are going to do is we are going to write a 1 here how did I get the 180 divided by 80 so you do the same below the line for our thousand five hundred divided by eighty and it gives you a total of 156.25 let's make it three now some of you might say that this doesn't make any sense you can't write the fraction like this and it's absolutely great you can't write fractions like this but this isn't a fraction this is a ratio this is nothing to do with maths or our fractions or anything like that so this is how we are going to write it it's 1 2 1 5 6 comma 3 now some of you will remember what this ratio is telling us it tells us that for every 156 comma 3 meters that we travel from point A to point B there will be an increase in height of 1 meter now what does this tell us about the slope it tells us that it's a very very gentle slope because you have to travel quite a long distance before there is an increase in of only one meter so the smaller this number yeah the steeper the slope so let's say there's another gradient and the answer is one to do then it means the slope is very steep because we're having two meters that you travel from point X to point y there's an increase in height of 1 meter and that is quite steep so I hope you understand how to calculate a gradient now I've also posted other videos on how to calculate distance I explained map different map scales in detail and I've also posted a video on how to do measure of bearing and so on so please feel free to click one of the links below if you need more information on some of these topics and remember to subscribe thanks for watching see you next time