Students in this video, let's learn how to find the area of a general quadrilateral.
All right.
Over here we have quadrilateral ABCDE.
Now let's join point B and point the.
All right.
So now you can see that we have got two triangles, right?
You have Triangle EBD and you have Triangle DBC And from this figure, it's obvious that if you find
the area of Triangle HDB and added to the area of Triangle DBC, that will be equal to the area of this
quadrilateral.
All right.
Now from Vertex M and Vertex C, let's drop Altitude's to cite Beadie.
But that would look like this now because these are all dudes.
These angles are 90 degrees and these sites will be the height of these two triangles.
Right.
So let this be a turn and let this be its.
All right.
So the area of the quadrilateral is equal to the area of triangle abody, plus the area of triangle
CBD already.
And we know that area of a triangle is half base in height.
Right.
So therefore this is equal to half beauty into each one plus half beauty into its two.
Right now, if the length of beauty is taken as deep, then we can see that the area of this quadrilateral
is equal to half B into X1 plus it's two.
All right.
Now, let's apply this in a very simple question.
Over here.
You have a quadrilateral and it's given that this diagonal over here is seven centimetre and this altitude
is two centimeter and this already is three centimeter.
All right.
Let's try to find the area of this quadrilateral so we know that the area of this quadrilateral is equal
to the area of this triangle, plus the area of this triangle over here.
But that would be half in to seven in the two plus half into seven into three.
Right.
Because the area of a triangle is half base height.
Now, this is equal to half in the seven to two plus three, which gives you seventeen point five centimeters
square.