Lesson video

Hello, my name is Miss Parnham.

In this lesson we're going to learn how to interpret gradient and intercept on real life graphs.

Here we have a graph showing the mass of a container in kilogrammes when it is filled with boxes.

And each box has the same mass.

So let's look at the Y intercept of the graph.

We can see that it intercepts at positive two.

And what does that represent? Well that means when there are zero boxes so when x is zero, y is two.

So it must be the mass of the container itself.

And what's the gradient of the graph? So we can pick any two coordinates that are easy to read, let's try 1,3 and 2,4.

We can see the vertical change is one and the horizontal change is one.

So that means the gradient is one divided by one or one.

And this means that every time we ad a box we add one kilogramme, so it represents the mass of each box.

So the empty container has a mass of two kilogrammes and each box has a mass of one kilogramme.

Here's a question for you to try.

Pause the video to complete the task and then restart the video when you're finished.

Here are the answers, on this conversion graph you could use any two pairs of coordinates to find the gradient.

It's probably easiest if one of them is 0,0.

So if we use say 0,0 and 5,4 then the vertical change divided by the horizontal change is four over five and you can leave that as 4/5 or call it 0.

8 either is acceptable.

And what does that actually represent? Well we've divided the price by the kilogrammes so it is priced per kilogrammes.

Here's another question for you to try.

Pause the video to complete the task and then restart the video when you're finished.

Here are the answers, when we work out the gradient we use two coordinates which are easy to read.

So for this graph we have 0,2 and 8,10.

The vertical change and the horizontal change you can see from those two coordinates are both eight.

So that gives us a gradient of one.

Eight divided by eight is one.

And we can see that this graph intercepts at two.

So regardless of the distance you go in the taxis there is standard charge of two pounds.

And then when we found the gradient by dividing the price by the distance.

So the gradient is the price per mile.

That's all for this lesson thank you for watching.