Is my answer correct?Watch
I'm not sure what else to do, I keep getting the same answer of A = 3 and for B = 2.5
Pick two points on the graph. Example: (0,4) and (6,6)
Then calculate the change in x and then calculate the change in y
Now use the values you have to calculate the gradient which is change in y over change in x.
Pick two points on the graph. Example (0,10) and (4,0)
Then calculate the change in x and the change in y again. This time you'll see that the change in y is negative because you do 0 - 10 = -10
Now use the values you got for B to calculate the gradient which is change in y over change in x. Your value here will be negative.
After that, there is a rule that you use to show if two lines are perpendicular
the gradient of the first line multiplied by the gradient of the second line = -1 (and this means they are perpendicular)
So m1 x m2 = -1 if they are perpendicular
So for the values you have substitute it into m1 x m2 and find the value.
If they are reciprocals of each other then they always multiply to give -1.
Hope this helps!
The squares on the grid are at right angles. For line A, if you go across 6 units, you go up 2 units. For B to be perpendicular, it would have to be that if you go across 2 units, you go down 6 units (think about what happens if you rotate going one unit across/up by 90 degrees). Since you actually go down by 5, they're not perpendicular.