In this video, let's discuss the Ford test for checking congruency of triangles.
It's called the R.
S Rule, and this is only applicable in the case of right angled triangles.
All right.
Now, this rule says that if you have two triangles, right.
And both of them should be right.
Angled triangles or you have a right angle triangle over here and you have another right angle triangle
over here.
Then if the hypotenuse it stands for the hypotenuse, if the hypotenuse of these two triangles are equal
and any side is equal to this side is equal to the side, then these two triangles are congruent.
Now what is the hypotenuse?
We will see more about right angled triangles further down in this course.
But just for this video, let's quickly understand it.
The hypotenuse is the side opposite to the angle of 90 degrees in a right angle triangle.
So if this angle is equal to 90 degree, then this side is what we call the hypotenuse.
And you will see that the hypotenuse is the greatest side in this triangle.
All right.
Now, what does the original rule say if the hypotenuse that's it's over here and any side of a right
angle triangle this order stands on right angle triangle are equal to the hypotenuse and one side of
another triangle, then the two triangles are congruent.
All right.
So we have a right angle triangle over here.
Let's call it ABC.
We have another right angle triangle over here.
Let's call it BQ or that we make some space over here.
And we have seen that these two should be right angled triangles on that angle, B, B, A, 90 degree
angle and angle to be a 90 degree angle.
And the hypotenuse should be equal.
That is AC is equal to be R and any other side.
So you have two more sides.
But let's take BCS equal to Q are in this case, these two triangles are congruent now to check whether
this is a valid test for congruency, just for our satisfaction.
Let's see whether I can construct a copy of Triangle ABC if I'm just given that angle B ninety degree
and I am given the length of X five centimeter and I'm given the length of X or centimeter.
All right.
We start with constricting.
Q are equal to four centimeter, then we draw a line from Q at ninety degrees.
So that line would go on like this.
Right now we take our compass, put the sharp edge at point R and we cut an arc on this line with a
diameter equal to five centimeters so that this length over here becomes five centimeter.
Now we get point B and we join B to Q which is already joined because we have drawn this line and we
join B to our.
So we are able to draw a copy of Triangle ABC without any ambiguity.
If we are just given these three pieces of information that is angle B is equal to 90 degrees.
We are given one side and we are given the hypotenuse.
Therefore, outages is a valid criteria to check congruency of two right angled triangles.